Rear brakes

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Rear brakes

Postby Mike Attew » Sun May 05, 2019 3:13 pm

Girling drum brakes all round, no servo. New slave cylinders and springs all fitted correctly. Brake peddle is hard and car stops fine. I haven't touched the brakes since I have had the car but I have noticed binding since it came back from spraying when I try to move it.

Adjusting the rear brakes until wheel spins, press brake peddle and rear wheels lock on. Brake fluid pressure doesn't seem to be releasing. I am thinking possibly the master cylinder.

I am still recovering from an op so can't look for the next 2 weeks so thought I would pick brains first.
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Re: Rear brakes

Postby 1972nail » Sun May 05, 2019 5:44 pm

Do the pistons move back in easily and release the brake if you release the pressure at the bleed nipple? If it doesn't then the wheel cylinder is sticking. If it does then pressure is being retained in the system. First check that the rear flexible hose is not swollen or damaged internally. That can cause the hose to act like a one way valve. Replacement is the only option. Damage can be caused by clamping the hose to prevent fluid loss while changing the cylinders.

If you are convinced that the hose and cylinders are not the problem then try slackening the rear brake pipe connection at the master cylinder to release any pressure that may be in the rear line. If the brakes release then it's the master cylinder that is holding the pressure on. Be prepared for fluid loss, wrapping a cloth around the connection would be a good idea.

However, It could also be a sticking pedal, but unlikely. But I would still check that there is no carpet or sound deadening around the pedal box and the mechanism.
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Re: Rear brakes

Postby rizzo » Sun May 05, 2019 7:22 pm

And while your working on the brakes CHANGE THE BRAKE FLUID! recommended replacement is 2 years generally, but is more often than not over looked :(
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Re: Rear brakes

Postby Mike Attew » Sun May 05, 2019 7:58 pm

Thanks. I forgot about the flexi collapsing. It could be that as both sides are locking the same.
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Re: Rear brakes

Postby StefanM » Mon May 06, 2019 7:18 am

Do not use copaslip like that around wheelcylinder rubbers. It is ordinary grease and brake rubbers will deteriorate over time.
I have seen people lubricate inside of wheelcylinders with copaslip also but hopefully you have not done that........
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Re: Rear brakes

Postby 1972nail » Mon May 06, 2019 9:39 am

Just another thought. The rear shoe adjustment needs to be carried out with the handbrake disconnected. Once the shoes are adjusted then the handbrake cable can be attached to both sides and the cable length adjusted.
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Re: Rear brakes

Postby Mike Attew » Tue May 07, 2019 3:45 pm

After a thorough check turned out the slaves were rusty inside although looked good on the outside. Fitted new slaves [ bought a pair as spares a few weeks back ] and changed the fluid and bled the system. All ok now.
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Re: Rear brakes

Postby 1972nail » Tue May 07, 2019 5:20 pm

Good result. :D
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