Pulls left on braking

[Bitsyncmaster]

I've always had a problem with the front drivers side brake since I've owned my car. I have SS pistons, new seals and SS brake lines and it pulls a lot of times when I brake. On my drive home today, I noticed it a few times and when I got home that drivers side wheel is definitely hotter than the other three.

Don't know what to do next. Are the front brake lines common so I can rule out the master?

[Mark D]

There is a single hard line coming out of the master for the front brakes, and then it tees off (Item 23) to the left and right. I don't think your MC is to blame in this case.

My first guess would have been that you've got a piston rusted solid on the PS, but since you're saying you have new SS pistons and seals you may just have a plugged up tee or plugged brake line that feeds the PS caliper.

Have you tried bleeding your brakes recently? If you can't get much fluid to flow on the PS vs the DS then that may be why your DS caliper is doing all the work and your car is pulling left.

http://dmctalk.org/attachment.php?attachmentid=11316&d=1340221899

[Bitsyncmaster]

I haven't tried to bleed it in a few years. I will get both front wheels off the ground and see that both wheel brakes release the same. This is what I did ling ago and from what I remember was the drivers side would have a little resistance turning the wheel and the passenger side had none after you brake.

[protodelorean]

Dave, pulling to the left is usually a sign of a problem on the right side. Both times I've had this problem on my cars, the problem has been with the rubber lines collapsing. If you're still running the original rubber lines, I'd replace them first.

[Bitsyncmaster]

Dave, pulling to the left is usually a sign of a problem on the right side. Both times I've had this problem on my cars, the problem has been with the rubber lines collapsing. If you're still running the original rubber lines, I'd replace them first.

I agree. The left brake is doing all the work. I have new SS brake lines on the front. Got the lines for the rear but never got around to putting them in.

[protodelorean]

OK. Next you need to get the front wheels off the ground and get an extra set of hands. Have someone turn the front wheels while you gradually push on the brake pedal. Based on what we know the left should lock up first. After the left locks up, continue to press further on the brake pedal to see if the right eventually locks up. Once it does, continue to press a bit, then as you release, have your partner trying to turn the right front. See if it releases when you release the pedal or if there's a lag (or possibly it stays locked). If it stays locked, release the bleeder screw on the right front caliper. If releasing the bleeder releases the wheel, then the line was holding pressure and the caliper is probably fine. If the wheel remains locked, the caliper is likely the problem.

(For reference, when I had collapsing lines, the restriction in the line caused fluid flow to be slowed BOTH WAYS. So applying the brakes, the caliper would be delayed in grabbing (if it ever grabbed) If I continued to push, eventually pressure would reach the caliper, but then when I released, the pressure would remain in the caliper/line for a while due to the restriction.)

[Bitsyncmaster]

OK. Next you need to get the front wheels off the ground and get an extra set of hands. Have someone turn the front wheels while you gradually push on the brake pedal. Based on what we know the left should lock up first. After the left locks up, continue to press further on the brake pedal to see if the right eventually locks up. Once it does, continue to press a bit, then as you release, have your partner trying to turn the right front. See if it releases when you release the pedal or if there's a lag (or possibly it stays locked). If it stays locked, release the bleeder screw on the right front caliper. If releasing the bleeder releases the wheel, then the line was holding pressure and the caliper is probably fine. If the wheel remains locked, the caliper is likely the problem.

(For reference, when I had collapsing lines, the restriction in the line caused fluid flow to be slowed BOTH WAYS. So applying the brakes, the caliper would be delayed in grabbing (if it ever grabbed) If I continued to push, eventually pressure would reach the caliper, but then when I released, the pressure would remain in the caliper/line for a while due to the restriction.)

Thanks. That sounds like a good plan.

[David T]

Another way to check if it's a bad hose is just to switch the 2 front hoses and see if the trouble moves with the hose. Since you say the hoses have been replaced it is more likely you have a problem with the right front caliper. I recently saw a recent rebuilt caliper get stuck. Water had gotten under the dust seal and rusted the caliper body making the S/S piston get stuck. Cleaned it all up and replaced the seals and it was fine. BTW, you have been flushing the brake fluid every other year, RIGHT!
David Teitelbaum




Thanks. That sounds like a good plan.

[Bitsyncmaster]

Both front wheels off the ground. Drivers side definitely requires more force to turn it than the passenger side. So I'm thinking the problem has to be on the drivers side. Pressed brake hard and tested again and results are the same.

I know the force to turn it is to high. That would explain why the wheel gets hotter but would hot brakes on that wheel make it pull that way?

[David T]

It pulls to the left (driver's side), because the passenger side caliper is not working. Rebuild the right, front caliper.
David Teitelbaum




Both front wheels off the ground. Drivers side definitely requires more force to turn it than the passenger side. So I'm thinking the problem has to be on the drivers side. Pressed brake hard and tested again and results are the same.

I know the force to turn it is to high. That would explain why the wheel gets hotter but would hot brakes on that wheel make it pull that way?

[Dangermouse]

Fwiw, I got my rear pads changed on the van recently. Apparently there is a knack in pushing the pistons in on this vehicle and the shop didn't know it.

The point here is that after I drove for 5 minutes there was a bad burning smell and the right rear wheel was untouchably hot. Upon examination it was the RR caliper that needed replaced.

In my case, the piston was stuck in the "on" position and wouldn't retract. Could this be Dave's case also?

David T, I take it that you are saying that Dave's RF is stuck "off" causing the LF to work more, hence causing the heating.

[David T]

It is normal for the brakes to heat up during use. If one stays cold then it is not doing any braking. Unless it is stuck on, but if it is pulling to the left the right side is not working. It is "stuck off". I have seen 'stuck on". Usually happens to both wheels when the pushrod for the master cylinder is adjusted a bit too long and is not allowing the calipers to release.
David Teitelbaum




Fwiw, I got my rear pads changed on the van recently. Apparently there is a knack in pushing the pistons in on this vehicle and the shop didn't know it.

The point here is that after I drove for 5 minutes there was a bad burning smell and the right rear wheel was untouchably hot. Upon examination it was the RR caliper that needed replaced.

In my case, the piston was stuck in the "on" position and wouldn't retract. Could this be Dave's case also?

David T, I take it that you are saying that Dave's RF is stuck "off" causing the LF to work more, hence causing the heating.

[Lenny]

I know this is really simple and I don't want to insult you but, did you check the tire pressure?

[Bitsyncmaster]

I know this is really simple and I don't want to insult you but, did you check the tire pressure?


Yes, tire pressures are good. This has been an off and on problem with my car for the six years I've owned it. My guess is the drivers side piston/cylinder are just binding but not always. I think I'm going to pull that caliper apart and measure the clearance. I may need to hone the cylinder.

I know just sitting up on jacks, turning the wheel by hand takes to much force. Hence the brake pads are still applying pressure.

[DMCMW Dave]

I may need to hone the cylinder.

.

There should be quite a bit of clearance between the cylinder and the piston (relatively) as the rubber seal is in the caliper bore. If the bore is not rusty there should not be an issue. I have heard of issues with SS pistons being just slighly oversize. Also SS pistons tend to expand more than steel when hot - do you notice any temperature sensitivity?

[Bitsyncmaster]

There should be quite a bit of clearance between the cylinder and the piston (relatively) as the rubber seal is in the caliper bore. If the bore is not rusty there should not be an issue. I have heard of issues with SS pistons being just slighly oversize. Also SS pistons tend to expand more than steel when hot - do you notice any temperature sensitivity?

I guess it's only a problem in the summer months. I will measure and post what I find and what I end up with after honing. The SS pistons were already in the car when I bought it.

[Ron]

If you are certain the left side is dragging, it could be that the bore has been worn/honed too much causing the piston to cock and bind (It happens more often as the pads get well worn.) If it doesn't ease up when you open the bleeder (make sure it isn't clogged), then I would replace the caliper(s) (especially since this has been a long term problem).

[Bitsyncmaster]

Pulled the wheel off and the hard line to the caliper. Still was dragging. Pried the outside pad a little and now it spins freely. The pads look good (thick and even). There is a little grease under the speedo cap but not enough to think the bearing needs replacing.

The heat and humidity has been real bad here so not in a rush to fix it yet.

[Bitsyncmaster]

Pistons are 2.125" dia. I need to clean the cylinders to get a measurement but from what I measure with them dirty is less than 2.125"

Anybody know what the OEM piston dia is? I would rather machine the pistons if those are in error.

There was a little crud under the outer seal but none below the piston O-ring.

[Bitsyncmaster]

I honed one cylinder clean and it looks like 0.0030 to 0.0035 of clearance. That seems about right to me. Honing will not remove much metal with the hone I have. It does not put much pressure on the stones. You do want to flood solvent onto the stones when your honing or else the stones will fill up. These are 220 grit stones and it gives a real nice finish.

So I'm guessing the cylinder walls were not finished good enough to prevent it from sticking.

[Bitsyncmaster]

Here are after and before honing.

[David T]

Dry fit the pistons in the caliper. The should slip in and out easily without sticking. Rotate the pistons and try several different positions. When you turn the caliper over the piston should drop out (of course you try this without the seals!). If a piston is out-of-round that may cause it to jam. If you do have to machine the pistons you must make sure the shop puts a very smooth finish on the outer surface so it doesn't leak. It has to be polished to be shiny.
David Teitelbaum





QUOTE=Bitsyncmaster;62229]Here are after and before honing.[/QUOTE]

[Bitsyncmaster]

The pistons have a mirror finish. I buffed them with my buffing wheel and polish. That's the one nice thing with the SS pistons. They never corrode. The pistons are also perfectly round, measuring in many locations.

[protodelorean]

Dave, you probably already did this, but while you have the calipers apart, double check all your fluid passages for blockages.

[Bitsyncmaster]

Dave, you probably already did this, but while you have the calipers apart, double check all your fluid passages for blockages.

Thanks. Did that. Had to cut the lawn tonight so it will be another night to get it back together. My outer seals look great. I had put new ones in the first time I worked on the breaks. But I saw some crap under those seals on the piston. Was wondering how I could make that outer seal "seal" better.

[Bitsyncmaster]

Got it back on the car. It still has some resistance to rotating the wheel after I brake and the passenger side has absolutely no resistance. When I do brake jobs on my daily drivers they have some resistance.

I still have some air in the line but need to pick up some more fluid. I bled it with my one man check valve bleeder. Think I will try vacuum bleeding it.

So have any of you noticed if after you break (wheels up) is there any resistance rotating the wheels?

[Bitsyncmaster]

I keep thinking about this problem. So when you take your foot off the brake pedal, it just releases the pressure and depends on the forces on the pads to move the pads off the rotors. I would guess there is some flex in the rotors as you make turns and some movement (sideways) of the wheel bearings that would end up making up some clearance between the pads and rotor.

But if one wheel does not match the other, then that pad will get all the clearance since the brake fluid line is common to both. So if you have air in the line, that would not change my problem since both front wheels will see the same pressures.

What I'm thinking will be the fix is to install springs on the pad holding pins to put more pressure on the release. I remember this discussed in the old forum but I think that was to eliminate noise.

I'm lost for other ideas unless somehow the passenger side wheel has an overly loose fit. But that side also has been cleaned and new seals installed at the same time I did it when I bought the car

[DMCMW Dave]

I keep thinking about this problem. So when you take your foot off the brake pedal, it just releases the pressure and depends on the forces on the pads to move the pads off the rotors.

Actually there is one other force at work. The rubber seals are "Square cut" which means that they actually "stick" to the pistons and flex outward very slightly when the brake is applied. This flex is what pulls the piston back in when you release the brake. As well as the minor warpage of the rotor kicking the pads back (this is what you mentioned).

The tension springs you see on some cars are very weak, as it would NOT be desireable to push the pads any distance off the rotor as this would increase pedal travel on initial application very dramatically. The purpose of those springs is to keep the pad from rattling in the space between the rotor and the piston, but not to aid in retracting the piston at all.

In your case it seems that the pad retraction is working better on one side than the other. OR the sticky one is working properly, and you have a warped rotor on the other side that is kicking the pads back too far. If this were the case the side that is opened too far has longer to go before the brakes engage, which will cause an apparent pull in the other direction. Here is a test for that - when you feel the pull, immediately let off and re-apply the brake. If the pedal travel is less and the pull is gone, you actually have one side over-retracting.

So - what to try? I'd take the tires off, pull the pads back, and spin the rotors looking for warpage. Depending on how the rotors warp you may not feel it in the pedal because as one piston goes out the other one goes in. (What most people feel and describe as warped rotors when braking is actually contaminated rotor surface, or rotors that are worn unevenly from side to side. A true warp is hard to feel.) If one rotor is excessively kicking back the pads you should see it.


Otherwise, I would replace the rubber O-rings in both front calipers. This also presumes that you have completely eliminated the brake hoses as a problem.

[Bitsyncmaster]

Thanks Dave. That makes sense the O-ring would pull it back a little. I will get a dial indicator onto the rotors and check those.

[David T]

There is another factor also. There is a small but measureable amount of play in the wheel bearings. As you turn to the left and right you are pushing the pads back a fraction too. To rule out a problem with the hoses just switch them from side-to-side. If the problem moves with the hose then you have a bad hose. At this point you have to consider even the unusual stuff. You very well could have a problem of mismatch with the front calipers. Be sure to torque the lug nuts in an alternating pattern. Examine the calipers and make sure everything is lined up and square. A bent bracket can cause unusual problems. The springs are only for noise control (clicking and squealing). In fact the OEM only had shim pads for squealing. Switch any and all parts you can side-to-side. If you can get the problem to move then you can figure out what it is. I would also now be checking the rear brakes. Maybe one is dragging or maybe a piston is stuck. The car should NOT be pulling to one side when you apply the brakes. In a panic situation that can become dangerous. Check the suspension for loose parts. If a lower control arm moves enough under braking the car would want to steer to one side. Have someone drive alongside and when you hit the brakes see if either of the front wheels moves much front-to-back.
David Teitelbaum





Thanks Dave. That makes sense the O-ring would pull it back a little. I will get a dial indicator onto the rotors and check those.

[Bitsyncmaster]

Turns out I did get all the air out since the brake pedal feels hard after it sat all night and subsequent presses end up with the same pedal movement. I did do a vacuum bleed on the other brakes anyway just to get new fluid in the system. That has to be the easiest way to bleed brakes since you don't get the pull back you get using the pedal.

I checked that there is just a little play in the pedal movement when fully released so the master is what stops it.

The rotors are parallel because as you turn them the force is the same for the full turn.

I still think I may play with some light duty springs just to see if that changes the drag from the drivers side to the passenger side. That would tell met it's just that the two sides are not matched in retraction.

By the way, the problem of more drag on one side is showing up even without rotating the wheel so the difference is not the rotors or bearings.

[Bitsyncmaster]

I played with some light springs and don't think that is the solution. The springs only push one side on the piston so that won't work.

My next thought is to put a finer (smoother) finish on the walls of the calipers. I'm thinking the retract forces are not even and that causes fiction at the bottom of the piston. My pads are very still very thick and the pistons are almost bottomed out.

[DMCMW Dave]

I played with some light springs and don't think that is the solution. The springs only push one side on the piston so that won't work.

My next thought is to put a finer (smoother) finish on the walls of the calipers. I'm thinking the retract forces are not even and that causes fiction at the bottom of the piston. My pads are very still very thick and the pistons are almost bottomed out.

Replace the rubber seals inside the calipers. That is the only part that has anything to do with what you are seeing, unless you happen to have a piston that is too big. The pistons should not be dragging on the bores at all, in fact you can test this by removing the rubber seal and dropping the piston in the bore.

[Bitsyncmaster]

Replace the rubber seals inside the calipers. That is the only part that has anything to do with what you are seeing, unless you happen to have a piston that is too big. The pistons should not be dragging on the bores at all, in fact you can test this by removing the rubber seal and dropping the piston in the bore.

That would be true providing the pressure on the pistion was square. The seal will be the only thing contacting at the top of the pistion but at the bottom, nothing holds it centered in the bore.

[DMCMW Dave]

That would be true providing the pressure on the pistion was square. The seal will be the only thing contacting at the top of the pistion but at the bottom, nothing holds it centered in the bore.

Keep in mind that the shims (this is the front?) actually put some off-center force on the pads/pistons on purpost and the system normally tolerates this, so for something to be pushing the piston so far off center as to get it to hang in the bore things would have to be pretty screwed up. I still think you are chasing a ghost. I've never seen a caliper bore cause a problem. Unless you have piles of rust in there,or pads that are worn at a very severe angle (which you have indicated are new) the problem is the seal or the piston.

Just for grins, measure the pistons (more than one) and the bore. It is is possible you got an oversize piston but I can't say I've ever heard of such a thing.

I'm also assuming that the pads are clean and not hanging up on the caliper. . . Common on barn cars, not so much on drivers.

[Bitsyncmaster]

One thing I have not done is meaure the bore the seal seats into. Maybe I got a caliper that was not machined correctly. I will have to see if I can measure that on both calipers.

[David T]

Or it is possible there is something wrong with the square seals you have. No way the piston should be getting stuck unless it is out of round or too big. I have never seen anything wrong with the calipers except being rusty and dirty. Even if they are corroded they will clean up enough to reuse.
David Teitelbaum



One thing I have not done is meaure the bore the seal seats into. Maybe I got a caliper that was not machined correctly. I will have to see if I can measure that on both calipers.

[Ron]

I'm also assuming that the pads are clean and not hanging up on the caliper. . . Common on barn cars, not so much on drivers.

This reminds me.... One of the pads in the last set I got from DMC had a glob of the black coating keeping it from sliding in. Scraping it off wasn't enough. It wouldn't go in on the other side like the others. It appeared that the plate was more broke rather than sheered on the the side with the excess coating, so I measured it and confirmed it was too big along the edge and trimmed it up with a file.
I'd bet it would of acted much like what is going on here even if it was just "tight"...

========

It seems that- the hydraulics have been eliminated because it drags with the bleeder open. And it is free until the pedal is hit the first time, then it drags whether the wheel is turned afterwords, or not, which eliminates the bearings, rotor, etc...so the caliper and pads are all that are left.
:dunno:

[David T]

I have seen pads that had to be filed and I have seen calipers rusty enough that they had to be cleaned up so the pads could move. They should NOT be jammed in so tight that they bind. You should be able to remove and insert them by hand.
David Teitelbaum

[Ron]

+1
I've seen bent pins and notches worn (in other types) cause a problem too...seems Dave would notice those by now though.


No way the piston should be getting stuck unless it is out of round or too big.
You never know if he is the first to hone the bore, and it is 30+ years old... You don't think it is possible for the o-ring to following the piston just enough to unseat it with the drag and pressure there in an over-sized bore, and cause a problem when the piston comes back? Granted not likely w/o eventually damaging it and/or leaking...but something abnormal is going on....

I'd have to get another caliper by now if for nothing but elimination...and figure out why later (I'm one of those who has to know why too ;-)

[DMCMW Dave]

We've rebuilt some pretty nasty looking calipers and never really seen a problem inside the bores.

That rubber seal is pretty thick.


+1
I've seen bent pins and notches worn (in other types) cause a problem too...seems Dave would notice those by now though.


You never know if he is the first to hone the bore, and it is 30+ years old... You don't think it is possible for the o-ring to following the piston just enough to unseat it with the drag and pressure there in an over-sized bore, and cause a problem when the piston comes back? Granted not likely w/o eventually damaging it and/or leaking...but something abnormal is going on....

I'd have to get another caliper by now if for nothing but elimination...and figure out why later (I'm one of those who has to know why too ;-)

[Bitsyncmaster]

Here is another thought.

How does an anti rattle pad work? What you want is the piston not pulling back as much. So the anti rattle pad makes the piston angle more into the bore to make it stick. I guess it will only make it stick causing friction on the piston and wall.

If you have other knowledge how it works, let me know.

[Bitsyncmaster]

Now my daily driver passenger side front brake is sticking. It's 104 today and will need to work on it.:hmm:

[Ron]

Anti-rattle (anti-squeal) pads (clips, shims, spray) all have the purpose of preventing brake squeal by dampening vibrations at the caliper-brake pad.

[Bitsyncmaster]

Anti-rattle (anti-squeal) pads (clips, shims, spray) all have the purpose of preventing brake squeal by dampening vibrations at the caliper-brake pad.

How does our steel "half pad" do that? By the way mine are full sized not like the half pad I remember with OEM pads.

[Ron]

:Headspin:
˙˙˙˙,uıʎɐs ʇsnɾ˙˙˙ʇɟǝl ƃuıɥʇou sı ǝɹǝɥʇ os `lǝǝɥʍ ǝɥʇ ƃuıuɹnʇ o/ʍ sƃɐɹp ʇı ǝɔuıs ƃuıɹ-o ǝɥʇ ɥʇıʍ ƃuıssǝɯ ssǝuʞɔıɥʇ ɹoʇoɹ ǝɥʇ uı ǝɔuɐıɹɐʌ ɐ ʇou s,ʇı puɐ uo ƃuıoƃ sı pɹıǝʍ ƃuıɥʇǝɯos `pıɐs ı ǝʞıl ʇnq `ʇɐɥʇ uo noʎ ɥʇıʍ ɯ,ı
We've rebuilt some pretty nasty looking calipers and never really seen a problem inside the bores.

That rubber seal is pretty thick.

[Ron]

How does our steel "half pad" do that? By the way mine are full sized not like the half pad I remember with OEM pads.It's softer metal...notice the imprint?

Most of the ones I have seen are full...I thought the old ones were superseded by the half ones they have now???
... Calling Dave S?

[DMCMW Dave]

I see very few full ones - and we take apart a lot of low-mile barn cars. I believe OE was the half-shim.

The shims are actually anti-squeel, not anti rattle, and I believe the way they work is that they keep the pad from landing "flat" and vibrating. Most current cars use them but they are a full size ship, so it must just be a damping effect.

[Bitsyncmaster]

I had pulled the caliper again. I tested the piston in the cylinder with no seal ring and it has plenty of clearance right to the bottom. So I don't think putting a smother finish on it will help but I'm going to do it anyway. I want to measure the seal seat but got side tracked fixing my daily driver. That passenger side brake locked up yesterday. There was no clue it was locked except my thought was my engine was not producing enough power. When I got home I smelled the brake burning and could not even touch the wheel it was so hot.

[Bitsyncmaster]

Some interesting findings with my daily driver (Malibu 2005). It's caliper is constructed the same as the D but only one piston. There was no sign of dirt, rust inside the caliper. The outside seal did have grease on it to help make the seal better. I'm guessing what happened was there was moisture in the fluid and it must have boiled yesterday in that 104 deg. heat. I guess I should have flushed the system before 7 years of use. This is an anti-lock system and the old fluid was dark. It still never got clear even after running a quart through the four calipers.

The piston had about the same clearance as the D. I noted the bottom of the cylinder did have shinny areas so it appears there is some side force on that piston when working.

So bleed the brakes in your daily drivers also.

[David T]

Actually you should always consult the manual for your specific car and follow the manufacturer's recommendations. As for ABS systems, you need to follow the procedures as detailed for each specific model and system. They are all different in how to flush and bleed them and how often. Some cars seem to be very tolerant of old brake fluid and others are so fussy you are supposed to flush every year! And there are a lot of different types of fluid nowadays so you have to check that you are using what you are supposed to use! As for your Malibu I would suggest you also replace the hoses, one is probably bad inside and if one failed you can expect the others to fail in the near future.
David Teitelbaum





Some interesting findings with my daily driver (Malibu 2005). It's caliper is constructed the same as the D but only one piston. There was no sign of dirt, rust inside the caliper. The outside seal did have grease on it to help make the seal better. I'm guessing what happened was there was moisture in the fluid and it must have boiled yesterday in that 104 deg. heat. I guess I should have flushed the system before 7 years of use. This is an anti-lock system and the old fluid was dark. It still never got clear even after running a quart through the four calipers.

The piston had about the same clearance as the D. I noted the bottom of the cylinder did have shinny areas so it appears there is some side force on that piston when working.

So bleed the brakes in your daily drivers also.

[Ron]

Some interesting findings with my daily driver (Malibu 2005). It's caliper is constructed the same as the D but only one piston. There was no sign of dirt, rust inside the caliper. The outside seal did have grease on it to help make the seal better. I'm guessing what happened was there was moisture in the fluid and it must have boiled yesterday in that 104 deg. heat. I guess I should have flushed the system before 7 years of use. This is an anti-lock system and the old fluid was dark. It still never got clear even after running a quart through the four calipers.

The piston had about the same clearance as the D. I noted the bottom of the cylinder did have shinny areas so it appears there is some side force on that piston when working.

So bleed the brakes in your daily drivers also.


FWIW, when those drag it is usually the tubes the calipers ride on. They are bad for brake dust etc to get in them keeping it from floating...
And make sure you turn the flat side on the tube's head toward the cutaway in casting...

[Bitsyncmaster]

From what I can measure, the ID of the grove that seats the seal is 2.333". I don't have an ID mic to fit it so that measurement may be off a few thousandths.

The seal has WHITE, BLUE, WHITE markings on it. I guess that is some color code to show the size.

The seal is much larger (ID) than the piston. So when the seal is installed it compresses a lot to end up tight on the piston.

I just hand sanded the bottom of the cylinder with 400 grit paper. The bottom should be the only part that could contact the piston on release.

I used AGS SIL-GLYDE brake grease on the "hat" seal to help keep water off the top of the piston.

Have not put the caliper back in the car yet. It's getting to hot outside.

[Bitsyncmaster]

Got it back in the car. I even squared up the pads within 0.001" measured at the for corners. Guess what.....
It still feels the same.:mad1:

It is definitely less then I started and I think it's less then the force I get on my daily driver. So I'm just going to keep an eye on it after test drives.

Next time you have the front up off the ground. Make some comments on the drag on the front wheels that you find.

[Bitsyncmaster]

That daily driver brake locked up again today. It went three months working great. I'm lost as to what to do about it. I guess it would be the master. I did not see a traction light from the ABS so I guess it did not brake that wheel.

[Bitsyncmaster]

Well my daily driver lockup goes away after it cools. My guess is the brake hose or the master is causing the rare lockup problem. So I replaced the brake hose since that is easy and less cost. That hose is only 1/8" ID. The old one would not drain fluid through it by gravity. Did not test the new one. Time will tell.

[Bitsyncmaster]

That hose is only 1/8" ID. The old one would not drain fluid through it by gravity. Did not test the new one. Time will tell.

You may find this interesting. I cut that bad hose and found it was collapsed right where they crimped a support bracket around the hose. You can not see any daylight through the hose but it would work fine when bleeding. So the high pressure opened it but the zero pressure would not release the brake.

[protodelorean]

My '88 Chevy truck did the same thing. In my case, that steel bracket around the hose had started rusting (and swelling) and squeezed down on the hose, cutting off flow.

[Ron]

You may find this interesting. I cut that bad hose and found it was collapsed right where they crimped a support bracket around the hose. You can not see any daylight through the hose but it would work fine when bleeding. So the high pressure opened it but the zero pressure would not release the brake.Yep, that is where they ALWAYS clog up. fwiw, the first thing I do if I can catch it hanging while on jacks is to crack the bleeder and if it spits much at all and/or allows the rotor to turn, take a pair of channel locks and roll the "crimp" around the hose open. Usually it frees up and I just buy a mate as the other side is almost always bad too...

[Bitsyncmaster]

Yep, that is where they ALWAYS clog up. fwiw, the first thing I do if I can catch it hanging while on jacks is to crack the bleeder and if it spits much at all and/or allows the rotor to turn, take a pair of channel locks and roll the "crimp" around the hose open. Usually it frees up and I just buy a mate as the other side is almost always bad too...

You were correct. The drivers side did the same thing yesterday. I knew it was the hose so just replaced it (found one at Auto-Zone). Same problem as the first hose failure.

[David T]

You were correct. The drivers side did the same thing yesterday. I knew it was the hose so just replaced it (found one at Auto-Zone). Same problem as the first hose failure.

Typically if only one wheel locks up you suspect the hose to that wheel. If all of the wheels lock up you suspect the master cylinder or the ABS controller. If you have ABS it is also possible for just one wheel to lock up but that depends on what kind of ABS system you have. I have seen hoses collapse where there is no crimp. The brake fluid gets in between the layers of hose and make it work like a check valve. From the outside the hose looks fine. If you have one wheel lock up it can also be the piston getting corroded and then stuck in the caliper. VERY common on a car that has been sitting for a long time and the brake fluid has gotten bad. You try to move it and use the brakes and the brakes lock up.