Brakes Binding When Hot

[Guest mdav1970]

Hi,

 

Has anyone had this problem that when the engine warms up they heat the brake pipes / reservoir above the exhaust manifold and the brakes start to lockup?

[Dave R]

does your brake pedal allow the master cylinder to fully return ??

[Guest kevin booth]

The return hole in master cylinder could be blocked, it is very small. I have had this before.

[Shaft]

Fashion a heat shield out of some alloy plate. Highly polish the side facing the manifold and see if that helps the issue.

[Guest chris brown]

Samsung dave R says it sounds as if the piston in the master cylinder isn't coming back all the way

[Guest 2b cruising]

Or, try heat wrapping your manifold. Material is cheap on fleabey, and it's supposed to be the in thing to do. It would cool your entire engine bay down if done correctly.

[Guest 2b cruising]

It will not help your master cylinder problem.

It really needs a service, clean out and new seals.

Easy job to do, just strip the parts out one by one and lay them out in order.

Have the new seals ready to replace the old to avoid any delay as summer coming on.

[Guest mdav1970]

So you dont think its down to the fact the brake pipes get hot as they sit above manifold? But more likely the piston is not returning? Wouldnt that also happen when cold?

[Bob Tucker]

If the pedal has no clearance, or the hole is blocked,

warmed (expanded) fluid cant return to the reservoir

but will force out the brake piston.

I reckon Dave has it spot on.

[Longboarder]

Yup. It's sort of both. But the warming and expansion of the fluid happens in all cars, added to by braking itself heating the brake fluid. Car manufacturers have known about hot brake fluid for years and make systems that allow for expanding fluid to get back into the reservoir. The hole that allows this is only uncovered when your foot is off the pedal and the piston fully retracted. Fitting these systems in kitcars disturbs the rest position and often the piston doesn't fully retract to open the fill/return hole. A shortening of the operating rod by 5mm would be a good starting point.

 

Nigel

[Guest mdav1970]

Hi Longboarder,

 

I have messed around with trying to get the best feel of the brakes by adjusting the length of the rod. I will probably move it back off again, as you said by about 5mm, add a heat shield above the manifold, perhaps also obtain a repair kit just in case none of these work. When i touch the brake pipes and cylinder after a drive they are reasonably warm, to hot.

 

Any ideas which and where to obtain the repair kit. The Cylinder is marked Ford and at the end has the digits C1404A stamped?

 

Thanks.

Edited March 26, 2015 by mdav1970

[Guest mower man]

I had a heat shield and manifold wrap but think that your prob is that you have taken the little bit of free play out of the pedal system for it to work as designed ,by the way have you removed the servo? mick

Edited March 26, 2015 by mower man

[Bob Tucker]

I had this happen to me on the way to an MOT test.

The brakes gradually started to lock on, until I couldn't drive any further.

Scratched my head for a bit, but eventually I found that a piece of the

floor carpet was wedged between the floor mounted pedal & the raised floor

stopping it returning.

Once removed, the pedal moved back about 1/8 inch (3.2mm for any youngsters!)

& the brakes released.

[Longboarder]

Personally I wouldn't buy a seal kit but would go for a new master cylinder. BUT you won't need one. Have faith and just back-off the rod to give free play and ensure the piston fully returns.

 

Nigel

[Guest mdav1970]

Havent removed the servo, i tried the brakes with servo disconnected before and i didnt like it. If i removed the servo altogther would it make the brakes feel any different than if i just blocked off the servo vacum pipe?

 

I will tonight slacken off the rod and pickup some ally from B & Q to make a heat shield which i recon would help anyways.

 

Who sells the adapter plates if i removed the servo,can't see any on the bay?