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Weird Brake Issue

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vanderbilly

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I'm a new member so please go easy on me. I have a 1956 100 Le Mans and although my brakes work fine, as in stopping the car effectively, I have another strange issue. When the car is cold, it rolls perfectly so I can push it in my garage without any assistance. However after I've driven the car for just a few miles, when I let off the gas I can feel the brakes gripping almost like a regenerative braking system in a modern car. Then when I get back to my house and park the car in the garage, I can't push it at all in neutral. However when I come back in about an hour and the car has cooled off, it rolls freely again. None of the drum brakes seem excessively hot and I don't know what to do. I do have a jack so I should probably drive it a couple of miles, then jack it up and see which wheels are locked up, sorry I just thought of that in the middle of composing this. Regardless does anybody have any experience with a similar issue or any ideas on what might be causing this?

Best regards
 
Sounds to me like the brake hoses have swollen internally so that the pressure takes some time to bleed off after you have applied the brakes. This is a common problem with Healeys with old hoses.
 
I would try checking your brake shoe adjustment first, you may have one or more of your adjusters a bit to tight to the drum I.D... Also I would do a general check of the brake springs and fitmemts, wheel cylinders and so on for starters. As mentioned above, old soft brake hoses are known issues as well.
 
A common cause of this condition is an incorrectly adjusted brake pedal pushrod. The manual specifies 1/8" of pedal free play before the pushrod moves the piston in the master cylinder.
 
Well I found my favorite new forum and thanks for the quick replies, Honestly I wasn't planning on checking back until tomorrow but I am pleased to see that this forum is active and full of helpful people. The brake hoses sounds like the culprit to me because when it's cold, the car rolls freely. I'll do some more checking and report back once I have some answers. Thank you again.
 
A misadjusted brake push rod can also roll freely when cold. It will affect all 4 brakes. A restricted hose will affect either one wheel(front) or both rear wheels. It would be a little unlikely to have all 3 hoses causing a problem at the same time.
Back in the 70'S when I first started driving what was then my fathers 100M, I made the mistake of adjusting the pushrod in attempt to improve pedal height. The car initially rolled freely, but I could feel the brakes start dragging the more they were used. If I let the car sit overnight they would go back to normal, and then start dragging again. It took me a while to realize that my 'adjustment' was the cause of the problem.
 
That's exactly the issue I'm having. Before I try anything I should probably take it out tomorrow and get it up to temp, bring it back, jack it up and check all four wheels to see which ones are sticking. I'll do that, post the results and hopefully that will help narrow it down a bit more. Again thanks for the suggestions. I'm a noob with this car so everyday is a learning experience. I've read the service manual cover to cover, twice.. so at least I'm learning the terminology and how they approached things back in the day. Happy to report that aside from this issue the car runs like a champ and I love driving the **** out of it.
 
Just a quick update to the watchers that I took the car our to get the brakes warm and the she broke down. Now I have what appears to be either a fuel or ignition related issue so once I get that resolved, I will test the brakes again and repost the results. Didn't want to appear as though I forgot to post brake results.
 
drambuie said:
I would try checking your brake shoe adjustment first, you may have one or more of your adjusters a bit to tight to the drum I.D... Also I would do a general check of the brake springs and fitmemts, wheel cylinders and so on for starters. As mentioned above, old soft brake hoses are known issues as well.
Click to expand...


ALWAYS think simple first.............had same problem..backed off the screw on the tight drum and works perfectly!!!!!!!! I think Drambuie NAILED it...


Pete
 
If it's a brake hose, just STANDING on the brake pedal (engine off, cold & while still in the garage) and then immediately attempting to roll the car, would be an easy enough test. While the heat may exacerbate the condition, if the hose(s) is/are breaking down internally, that should quickly prove/disprove the swollen theory. Oh, and it's a real thing, because my rear rubber hose__which wasn't really that old__was causing the same symptom (and it only takes 1 wheel/1 axle braking to keep a mere mortal from rolling the car).

Once the car is running again, if you have an infrared temperature gun, pointing it all four (4) brake drums after a spirited drive will indicate corners running significantly temperatures higher/lower than others.
 
I wonder what the recommended useful life of brake hoses is? Ten years, maybe, or more? Remember when we kept our tires forever as long as they had some tread?
 
Bob_Spidell said:
I wonder what the recommended useful life of brake hoses is? Ten years, maybe, or more? Remember when we kept our tires forever as long as they had some tread?
Click to expand...
My failed replacement hose was probably somewhere in the 8-12 year range (more likely the 10-12 timeframe); certainly replaced in Ohio not long after getting the car back from Paul Tsikuris/prior to being roadworthy (always a relative term with Healeys...).

I'm hopeful that the Teflon/braided SS hoses aren't subject to deterioration... (they were not yet available__or at least listed**__ for 2-seaters when I last replaced the rubber hoses.



** I believe the rear hose is longer on the 2-seater; obviously the fronts are the same as 4-seaters.
 
Update to those who are interested. Adjusted the brake push rod and bingo.. brake problem disappeared. Thanks for the help! Now I'm off to install a new gas tank as my 60 year old tank is full of sludge.
 
vanderbilly said:
I'm a new member so please go easy on me. I have a 1956 100 Le Mans and although my brakes work fine, as in stopping the car effectively, I have another strange issue. When the car is cold, it rolls perfectly so I can push it in my garage without any assistance. However after I've driven the car for just a few miles, when I let off the gas I can feel the brakes gripping almost like a regenerative braking system in a modern car. Then when I get back to my house and park the car in the garage, I can't push it at all in neutral. However when I come back in about an hour and the car has cooled off, it rolls freely again. None of the drum brakes seem excessively hot and I don't know what to do. I do have a jack so I should probably drive it a couple of miles, then jack it up and see which wheels are locked up, sorry I just thought of that in the middle of composing this. Regardless does anybody have any experience with a similar issue or any ideas on what might be causing this?

Best regards
Click to expand...
G'day vanderbilly, and welcome to this forum. We promise to go easy on you! I believe Steve Byers has given very sound advice. The rubber brake hoses can collapse internally so from the outside they look fine. I once had this happen to the clutch on a mini. The clutch was reluctant to take up and gave the impression of a worn out plate. After I replaced the clutch & pressure plate there was no improvement. It was then that I discovered that the hydraulic hose needed replacement. The pressure of your foot is enough to force the fluid through the hose but there isn't enough force from the brake shoe return springs to overcome the blockage. If one hose is suspect, best to replace all three to be sure.
Cheers,
Alwyn
 
Seein' as how Vanderbilly's post is over seven years old and he's no longer a BCF member ...

bigtwiels said:
Whenever I step on the brakes hard the engine dies...any ideas?
Click to expand...

I'm thinking your 1980 MGB has a major problem with the power brake booster!
 
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