Puddle of brake fluid

[Flash66]

Hi Gang,

Found a puddle of brake fluid under my car today. Looks like it's coming from the brake master cyl area. The clutch master would leak inside the car correct? I just rebuilt my calipers a few weeks ago and maybe I worked the hell out of it while bleeding? The res was not really low but it's a pretty nice puddle. Is this common when the seals fail to leak onto the floor in this area? Thanks!!http://tapatalk.imageshack.com/v2/14/11/21/45ba69f4842e310c1032d66539e5ffb9.jpg

[Rich]

Too soon to say it has to be from the brake master.

The clutch master is up there, too, outside the passenger cabin. As well as its remotely-connected fluid reservoir.

Clean it up soon. ALL of it. That stuff eats the paint on the chassis and the fuel tank closing plate. Any paint anywhere, in fact.

Not sure how bleeding the brakes would make the brake master or any brake connections leak unless you had the master out to bench-bleed it and you didn't reconnect the lines well.

[Flash66]

I see my pic didn't post. Here it is. 31670

[Flash66]

So here is with the inspection cover off. The bottom of the booster and top of the tank is wet. Weird thing is the brakes feel fine. So it appears to be leaking between the master and booster. Is this a bad seal?http://tapatalk.imageshack.com/v2/14/11/21/7b2225a5734cc22d680d2a7320b99147.jpg

[Rich]

Hard to say, even with the photo.

1. Check the clutch reservoir level (left of fuel filler) just for fun.
2. Pull both of the access panels in the trunk. The vertical one in front of the fuel filler lets you see if the clutch master and its reservoir/hose are OK. The flat one over the brake master lets you see/feel if it's dripping.

You need to pull off one or the other anyway to try to clean up the mess from the source.

Yes, the clutch master CAN leak inside the cabin and the brake master cannot. But the clutch master's plumbing connections are all outside the cabin - where they can also leak.

[Flash66]

31671
I hate tapatalk!

[Rich]

So here is with the inspection cover off. The bottom of the booster and top of the tank is wet. Weird thing is the brakes feel fine. So it appears to be leaking between the master and booster. Is this a bad seal?http://tapatalk.imageshack.com/v2/14/11/21/7b2225a5734cc22d680d2a7320b99147.jpg

And there is a photo in there? OK, seeing it now.

[dn010]

Pull the master cylinder, looks like the cause to me, no? It even looks really low on fluid...

If you have a leaking seal but enough fluid your brakes will still work like they are "normal", until you run out of fluid....

[Rich]

Please also report on the clutch reservoir hose connections. All nice and dry? Reservoir full? Clutch master is dry?

[Flash66]

Thanks guys. I just got through cleaning up the mess. The clutch cyl is full and dry around all connections. It appears to be mainly between the booster and master connection. I guess it's time for a new one!

[DMCMW Dave]

Thanks guys. I just got through cleaning up the mess. The clutch cyl is full and dry around all connections. It appears to be mainly between the booster and master connection. I guess it's time for a new one!

The master is leaking. There is actually a drain/relieve cut into it so that the fluid can run out rather than pool in the booster.

Also take the gas tank cover plate off, scrape all the loose epoxy off on the inside and the outside, and repaint it. Don't ignore it, by now there is no epoxy on the inside and it will rust away as water stays in there.

[PJ Grady Inc.]

The master is leaking. There is actually a drain/relieve cut into it so that the fluid can run out rather than pool in the booster.

Also take the gas tank cover plate off, scrape all the loose epoxy off on the inside and the outside, and repaint it. Don't ignore it, by now there is no epoxy on the inside and it will rust away as water stays in there.

Good Advice Dave. The paint (undercoat on epoxy) is already lifting in the picture and will cause severe rusting in short order. The orange tag on the master indicates that if it is not the original one on the car then it's still a 33 year old NOS replacement but it looks original to me. The recent fluid flush caused what was left of the original seals to bite the bullet and bleed all over. That's an unusually severe leak for a BMC.
I always recommend changing the master when doing calipers unless the system has had at least a recent brake flush or a recent BMC replacement (Say within 4 or 5 years). Few things are more dangreous than losing your brakes suddenly which could have been the case here!

The other thing which could have caused a similiar leak is a split clutch reseviour hose but that's not the problem here. That's an item that's typically overlooked when changing clutch hydraulic's and all of the original ones are way overdue for replacement. Sorry for straying from the current problem but I figure it's good to put it out there.
Rob Grady

[David T]

Good Advice Dave. The paint (undercoat on epoxy) is already lifting in the picture and will cause severe rusting in short order. The orange tag on the master indicates that if it is not the original one on the car then it's still a 33 year old NOS replacement but it looks original to me. The recent fluid flush caused what was left of the original seals to bite the bullet and bleed all over. That's an unusually severe leak for a BMC.
I always recommend changing the master when doing calipers unless the system has had at least a recent brake flush or a recent BMC replacement (Say within 4 or 5 years). Few things are more dangreous than losing your brakes suddenly which could have been the case here!

The other thing which could have caused a similiar leak is a split clutch reseviour hose but that's not the problem here. That's an item that's typically overlooked when changing clutch hydraulic's and all of the original ones are way overdue for replacement. Sorry for straying from the current problem but I figure it's good to put it out there.
Rob Grady

My theory of why the master cylinder starts leaking after rebuilding the calipers is that the bore of the master cylinder is badly corroded all the way in and normally the seals won't get there during normal operation. That's why the corrosion builds up in that portion of the bore. When you rebuild the calipers and bleed the system NOW you push the seals all the way in (the pedal goes ALL the way down) as you stroke the master cylinder to the limit. Forcing the seals over all of that corrosion tears them up and now they start leaking. Bottom line, if the brake system is that bad that you had to rebuild the calipers you can bet the master cylinder is also in need of being rebuilt/replaced too. This all starts because the brake fluid has not been flushed often enough and corrodes the insides of the brake hydraulics. That corrosion tears the seals up when they pass over it. The take-away lesson here is to flush and bleed the brakes (and the clutch on the 5-speeds) EVERY TWO YEARS! A whole lot cheaper than replacing calipers and master cylinders and the collateral damage to the carpet and frame coating. Never mind the brakes are a primary safety system and MUST be reliable. One of the fastest ways to get your Adrenaline pumping is to push on that brake pedal, have it go to the floor, and not feel the car slowing down!

[PJ Grady Inc.]

My theory of why the master cylinder starts leaking after rebuilding the calipers is that the bore of the master cylinder is badly corroded all the way in and normally the seals won't get there during normal operation. That's why the corrosion builds up in that portion of the bore. When you rebuild the calipers and bleed the system NOW you push the seals all the way in (the pedal goes ALL the way down) as you stroke the master cylinder to the limit. Forcing the seals over all of that corrosion tears them up and now they start leaking. Bottom line, if the brake system is that bad that you had to rebuild the calipers you can bet the master cylinder is also in need of being rebuilt/replaced too. This all starts because the brake fluid has not been flushed often enough and corrodes the insides of the brake hydraulics. That corrosion tears the seals up when they pass over it. The take-away lesson here is to flush and bleed the brakes (and the clutch on the 5-speeds) EVERY TWO YEARS! A whole lot cheaper than replacing calipers and master cylinders and the collateral damage to the carpet and frame coating. Never mind the brakes are a primary safety system and MUST be reliable. One of the fastest ways to get your Adrenaline pumping is to push on that brake pedal, have it go to the floor, and not feel the car slowing down!

I totally agree with your theory and maintenance schedule but very few people do 2 year flush routines. You are preaching to the choir but even the choir gets lazy sometimes;)

[Flash66]

I really appreciate all of the advise guys! Luckily I live in the desert where humidity is like 5% so I'm not concerned with immediate rust. I had the tank out several years ago and reconditioned that part of the frame and tank plate so there wasn't much epoxy in that area anymore. This is also an 83 (16811) that was on consignment at Rob Grady's back in 97 according to some old docs I have. My point is that the frame is slobbed over with undercoating that's going to make it a dirty job. I'll pull the cover, clean and POR-15 everything.

[David T]

I really appreciate all of the advise guys! Luckily I live in the desert where humidity is like 5% so I'm not concerned with immediate rust. I had the tank out several years ago and reconditioned that part of the frame and tank plate so there wasn't much epoxy in that area anymore. This is also an 83 (16811) that was on consignment at Rob Grady's back in 97 according to some old docs I have. My point is that the frame is slobbed over with undercoating that's going to make it a dirty job. I'll pull the cover, clean and POR-15 everything.

Undercoating does make the whole job messier. Scrape off what you can and Eastwood.com has a good spray to remove undercoating. Again very messy. As for the 2 year flush schedule, it is better than rebuilding the brakes and if you think that is overkill, in the Lotus world it is EVERY year. For Lotus's it is also about overheating the brake fluid and if it gets too old it gets too high a moisture content and you can boil the brake fluid. Once the fluid boils you lose all pedal. At the very least if the fluid starts to look dark and thick in the reservoir you are past due. As an owner of a Delorean there are things that go bad over time no matter if the car is used or not. Among them are:
Brake (clutch) fluid
Anti-Freeze
Tires
Battery
Struts
Wiper blades
All owners should track these items and after a certain time or mileage replace them.

[Flash66]

Well, I dropped the tank plate today. As soon as I jacked up the front of the car, you wouldn't believe the amount of brake fluid that started to run out of the back of the plate on an incline. For a second there I thought I had a fuel leak due to the location. Let me say one thing here guys, this whole ordeal sucked! Brake fluid was all over the frame as well. As precious as we all hold our frame integrity standards, if you have the original Girling MS like I do REPLACE IT NOW! Don't be cheap and put this off. It needs to go period before you end up having a day from hell like I did. This was 10 times worse than old stinky gear oil cleanup! Two things in the world that are pure evil to me is pink home insulation and GD brake fluid!

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[Steven]

I think I ran into the same problem. With spring arriving I uncovered the D from hibernation and found a rather large oil spill in the same spot. I'll attach a few pictures, any suggestions?

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[David T]

Check the fluid levels in the brake master reservoir and the clutch reservoir. If they are low (or empty) you can assume where the puddle came from. If you have been reading all of the posts and the other similar threads you know what you have to do.

[Steven]

Just pulled the tank plate off, definitely have to clean this guy up!

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[dustybarn]

Another possibility is that the brake fluid is leaking past the grommets that seal between the MC and the reservoir. In this case the brakes would still feel fine, as you reported. This happened to me, and the pattern of leakage looked just like yours. It LOOKED like it was coming from between the booster and MC, but it wasn't.

[DMCMW Dave]

Another possibility is that the brake fluid is leaking past the grommets that seal between the MC and the reservoir. In this case the brakes would still feel fine, as you reported. This happened to me, and the pattern of leakage looked just like yours. It LOOKED like it was coming from between the booster and MC, but it wasn't.

There is no real seal between the brake master and the reservoir (well there is sort of PN105544, but there is a huge vent hole in the casting of the master that goes right around the seal). The real fluid seal is the master itself, and if the master leaks the fluid will run out of the vent, down the outside of the booster, and into the gas tank area.

[David T]

There is no real seal between the brake master and the reservoir (well there is sort of PN105544, but there is a huge vent hole in the casting of the master that goes right around the seal). The real fluid seal is the master itself, and if the master leaks the fluid will run out of the vent, down the outside of the booster, and into the gas tank area.

That leak path is there for 2 reasons. One, if the leaking brake fluid was directed into the booster you would never know the master was leaking and it would take a LOT of fluid to fill it. Two, it would then also damage the booster. Same logic for the water pump weep hole, so the bearings won't die (at least not right away) and you KNOW you have a leak. It is one of the areas to be checked when inspecting the car.