Parking Brake Adjustment Problems

[spikeygg]

I've been looking through the forums and I've found a little bit of info on the parking brakes here and there...

hand brake/e-brake/parking brake adjustment question (http://dmctalk.org/showthread.php?12187-hand-brake-e-brake-parking-brake-adjustment-question)
Parking break pads replacement (http://dmctalk.org/showthread.php?11494-Parking-break-pads-replacement)
Rebuild Your Brake Caliper (http://dmctalk.org/showthread.php?1939-Rebuild-Your-Brake-Caliper)


My car has been in the family since it was built and ever since I can remember the parking brake hasn't worked well. After reading a bunch about it I went out and pulled the tires off to have a look. The driver's side was locking up pretty good but the passenger's side was free-wheelin'. I read that the clamping bolt can be tightened so I went and did that but I noticed that the adjustment is very coarse, you have to spin the bolt by 180 degrees to get the locking cotter pin installed.

While I was messing with it, I found that if I adjusted the bolt so that the parking brake lever worked and held the tires then the parking brake pads were dragging on the disc (rotor was difficult to spin by hand). If I relieved the pressure on the pads so there was no drag, then the parking brake did nothing when it was pulled. Is there something I am missing here in the adjustments? I feel like there needs to be another "knob" to getting this dialed in.

44623

I studied the system for a little while and found that the brake pads don't flatly contact the rotor. They appear to contact the rotor at an angle, just like Dangermouse mentioned (http://dmctalk.org/showthread.php?12187-hand-brake-e-brake-parking-brake-adjustment-question&p=176913&viewfull=1#post176913) in the top thread I included above. I guess I'm wondering a few things:


I'm sort of assuming that this will solve the issue, do any of you have experience with it?
Can existing pads be sanded/shaved to fix the taper so that they do contact the rotor squarely?
Is there any company that sells the properly tapered brake pads?


I've also read that there is an auto-adjusting mechanism, and I know David T, that: "it doesn't work". However, I wonder if it can be made to work at least a little by completely cleaning/rebuilding/greasing them properly like DeCobra showed (http://dmctalk.org/showthread.php?1939-Rebuild-Your-Brake-Caliper&p=24717&viewfull=1#post24717) in the bottom thread I shared above. ... or are we doomed to have to fiddle with it and have parking brakes that drag or don't work all the time?

Seriously, I remember a point in my past when our neighbors came over and told us that our car had rolled into the street by itself, this was like 20 years ago.

Thanks for listening to me rant. :)
-Greg

[Bitsyncmaster]

Yes you can sand the pads to level them. Use a very coarse sand paper and they cut pretty quickly.

I adjusted my park brakes when I first got my car about 8 years ago. I don't remember the procedure much but I jacked the rear end up so I could spin both tires and adjusted so they both locked after 3 or 4 clicks of the brake handle. They seem to hold pretty well. I can torque the wheel nuts to 70 ft/lbs without the brakes slipping.

[Drive Stainless]

Step one is to take the slack out of the cable. You need to do this at both ends of the parking brake cable. It is correct when pulling up on the parking brake lever begins to move the pads. Step two is to turn the adjustment screw so the wheels are locked up tight after 3-4 clicks on the lever.

[David T]

Don't waste you time with the automatic adjuster. You can also make a slight adjustment turning the nuts holding the outer cable to the bracket on the caliper. Make sure both pads in each caliper move easily on their pins, often one or both get stuck and won't move or won't move easily. If necessary remove the pins holding the E pads, clean everything up and reassemble with some Never Seize. You should not have to sand the pads. Be careful, after so many years I have seen the pad materiel just fall off, the glue fails to hold it to the metal backing pad. If it does come loose and you still have the brake materiel, you can reglue it with some Gorilla Glue. That screw IS a course adjustment but most of the time it works. If you do get the adjusters to work document it so we can all benefit from your experience. IMHO it isn't worth it, under normal use the E brake pads just don't get very worn unless they are dragging.

[Jonathan]

Chris also wrote a how-to on this a few years ago. I didn't see it in the links you mentioned so here it is.

http://dmctalk.org/showthread.php?3495-How-to-adjust-your-Parking-Brake

EDIT: there is also a DMC Knowledge Base article on the subject: http://support.delorean.com/kb/a73/parking-hand-brake.aspx

[FABombjoy]

I just completely refreshed my parking brake setup. Fully cleaned all parts, new springs, properly greased, spent lots of time on it. Still won't auto adjust.

If I took it apart again I'd probably cut another cotter pin channel in the adjusting screw. Seems like sometimes the half turn to line up the pin is too much / not enough.

[spikeygg]

I just completely refreshed my parking brake setup. Fully cleaned all parts, new springs, properly greased, spent lots of time on it. Still won't auto adjust.

If I took it apart again I'd probably cut another cotter pin channel in the adjusting screw. Seems like sometimes the half turn to line up the pin is too much / not enough.

Thanks man, this exactly answers my question. What a pity. I might attempt the full clean/grease etc. if there was some payout like working brakes.


You can also make a slight adjustment turning the nuts holding the outer cable to the bracket on the caliper.

I'm gonna have to try the rear adjustment mechanism and see if I can adjust out this problem but I'll likely have to sand the pads to make them taper correctly. I'm guessing I just back off the nut that is toward the center of the car and then tighten up the one that's toward the outside of the car to make the cable pull a bit more?

44645

[FABombjoy]

Thanks man, this exactly answers my question. What a pity. I might attempt the full clean/grease etc. if there was some payout like working brakes.
It seems like the adjustment is too course for our cars. I bench tested the mechanism and was surprised when it didn't work once installed. I wonder if it worked better in Jaguar cars. They may have had a different cable/lever setup that was more optimal for the design.

[Bitsyncmaster]

I'm gonna have to try the rear adjustment mechanism and see if I can adjust out this problem but I'll likely have to sand the pads to make them taper correctly. I'm guessing I just back off the nut that is toward the center of the car and then tighten up the one that's toward the outside of the car to make the cable pull a bit more?

44645

I don't remember a cotter pin when I did my adjustments so I must have done the cable adjustment. You really don't need self adjustment since the parking brake pads are not worn down any.

[dn010]

While it isn't the "right way": I adjusted the large slotted screw/bolt to where the pads wouldn't drag but where they weren't too far away. This adjustment hasn't always ended with the slot of the screw aligned with the holes for the pin, so I'd install the pin in the top hole, bow it out and over the adjusting screw and then back into the bottom hole where I'd bend the ends of the pin outwards as usual. I've never had a screw move even slightly like this in 14 years. If you're worried about it, cut another line or two into the screw head.

[spikeygg]

So I went out and tried really messing with the nuts in the back by the bracket and they don't affect the brake pad separation. They appear to only change the amount of slack in the cable.
When I tightened up the driver's side nuts quite a bit, the parking brake handle wasn't under any tension from the driver's side cable. When I loosened them a bunch I found that the parking brake handle was under so much tension that it didn't stay disengaged.
I adjusted them so that they are tight but allow the handle to stay disengaged when the button is pressed and the handle is released.

[David T]

The e-brake pads are "separated", ie, released, by #39 section 6-2-1, a metal 2 pronged clip. The pads move so little that you are actually bending that clip a little when you lock the brakes and when you release them the clip tries to straighten back to it's original position, spreading the pads. It may be that the clip is over-bent and needs to be straightened out so it will spread the pads. Both cables must be able to move freely, you may need to lubricate them so they each move evenly and smoothly. If a cable is binding that clip is not strong enough to separate the pads. On the brake lever assembly, #1, there is an equalizing plate that swivels a little taking up a little difference between the left and right cables. Make sure all of the links move freely so it can equalize.

[FABombjoy]

On the brake lever assembly, #1, there is an equalizing plate that swivels a little taking up a little difference between the left and right cables.
This is one of my favorite engineering pieces on the car. If one of the cables pops out of that plate, you lose braking on both sides!

[Horsebox]

http://uploads.tapatalk-cdn.com/20160721/3cad3ab376516fef3909c250c31907cf.jpg

Bit of a ballache but quicker to grind down than it looks if you use coarse sand paper. Cleaning the disc afterwards took longer.

[David T]

This is one of my favorite engineering pieces on the car. If one of the cables pops out of that plate, you lose braking on both sides!

Plenty of cars have a similar system. If a cable brakes or otherwise comes undone you lose it all! At least on a 5-speed you use the brake all the time so you would know if it doesn't work. On the automatics we NEVER use it and if it isn't checked occasionally who knows if it will work if needed?

[Tillsy]

On the automatics we NEVER use it and if it isn't checked occasionally who knows if it will work if needed?

This is a topic that puzzles the absolute bejesus out of us Aussies. People get confused about the digital transmissions on many cars, such as my Jeep, and somehow seem to not know they have accidentally put their car in neutral instead of park. Anton Yeltsin's recent death being a prime example.

As a country where the very first lesson you learn in a car is to apply the hand brake (not emergency brake) at all times it baffles us why you guys instead treat it as an emergency brake. It is evident in all American television shows and movies - someone stops a car, steps out, and as they do you see the car jerk slightly because the transmission is grabbing the car... whereas here in Australia a car doesn't budge a single inch because we put on the hand brake.

Off topic, just fascinating that you guys actually make a bold point of "NEVER" using the thing when in an automatic.

[David T]

This is a topic that puzzles the absolute bejesus out of us Aussies. People get confused about the digital transmissions on many cars, such as my Jeep, and somehow seem to not know they have accidentally put their car in neutral instead of park. Anton Yeltsin's recent death being a prime example.

As a country where the very first lesson you learn in a car is to apply the hand brake (not emergency brake) at all times it baffles us why you guys instead treat it as an emergency brake. It is evident in all American television shows and movies - someone stops a car, steps out, and as they do you see the car jerk slightly because the transmission is grabbing the car... whereas here in Australia a car doesn't budge a single inch because we put on the hand brake.

Off topic, just fascinating that you guys actually make a bold point of "NEVER" using the thing when in an automatic.

Most drivers don't even know how to drive "stick" and most drivers don't know HOW to apply the E Brake if they even know where it is! A while back there was a horrible accident where a floor mat jammed the gas pedal in a Toyota in California. The family all died because the driver didn't think to shut the motor of and use the e-brake. Caused a huge recall.

[content22207_2]

"Parking Brake" actually.

Don't believe Hollywood movies. Cable operated parking brakes are not effective at all against a rev'ing engine. Air brakes and electric over hydraulic brakes are, but not cable operated brakes. They're OK to hold a static vehicle, but not a vehicle pulling against them. World is full of stretched cables and worn off pads/shoes on vehicles that the driver forgot to release the parking brake.

That said, cable operated drum shoes are more effective than cable operated disc pads simply due to their larger surface area.

Combine larger drum brakes with the force of air or electric motors and you have a parking brake that can *SOMEHWHAT* compensate for failed service brakes (once you dump the air or engage the electric motors the wheels will lock up completely, making the vehicle very difficult to control, but the wheels will stop turning...). Personally I'd lock up the wheels as a last resort, especially on a commercial vehicle (electric parking brakes on my school bus only lock the rear wheels -- it should be more controllable than an air brake vehicle if I flip the switch because I'd still have use of the steering axle).

Speaking of commercial vehicles: this comment appeared in Post #15: "On the automatics we NEVER use it and if it isn't checked occasionally who knows if it will work if needed?" By federal law commercial drivers must check proper functioning of the parking brake every single time the vehicle is used, transmission irrespective. Guess that's why CDL drivers pay for an expensive license rather than the cheap one.

Bill Robertson
#5939

[Horsebox]

It's interesting how difficult each country makes it to keep these cars on the road.

In the US you have to worry about emissions, perhaps even to the extent of keeping the lambda system working to pass the test. Does much else get tested?

In the UK, for this age of vehicle, yearly test doesn't really care much for emissions or exhaust CO content, but your hand/parking/e brake better be working right or its back to the garage.

[content22207_2]

No national standard -- each state sets its own inspection requirements, both safety and emissions (some states, such as South Carolina, have no inspections whatsoever).

North Carolina stops inspecting after 35 years -- my DeLorean just aged out.

Federal government does require a standardized annual commercial vehicle inspection (trucks, buses, etc).

Bill Robertson
#5939