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RobTR3

Rear Brake Rubbing

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I wonder if members could help me out with a recurring problem.

The N/S  rear brake  will bind after a period of driving , perhaps 20 miles or so. I can hear the noise after slowing down. I don't get this problem initially into the drive  and all seems well for some time. It only affects the N/S rear brake. I have done the following in order to get on top of this, but so far to no avail -

New rear wheel cylinders. Wheel cylinders slide on backplate Ok and new spring plates installed.

New return springs. 

New master cylinder seals and completely new brake fluid.

Swapped drum and shoes from O/S to N/S to see if any variation, but nothing changed.

The rear brake hose is newish.

Brake pipe to wheel cylinder renewed recently.

Brakes adjusted correctly including handbrake cables. No issues with brake adjusters.

Brake shoes are not worn or distorted and swapping from O/S would have highlighted any problems with shoes or drums I would have thought.

No brake compensator fitted. In any case, I thought these were to resolve front brake binding issues.

When the car is in the garage after a run and I jack it up and rotate the N/S rear wheel, the wheel rotates OK without any noise!

I did think it maybe a wheel bearing, but surely the noise would be continuous from the start of a run to the end?

I am stumped with this, any suggestions will be greatly appreciated. 

Rob

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Hi Rob

If the brakes are binding i would expect them to get hot

is the offending side hotter than the other side after a run?

steve

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9 minutes ago, RobTR3 said:

 

 

When the car is in the garage after a run and I jack it up and rotate the N/S rear wheel, the wheel rotates OK without any noise!

 

.

 

 

 

Hi Rob,

             is the above immediately after a run - within a couple of minutes.  If not then go for a run. Get the noise and then stop, jack it up and test the wheel.

It could be a wheel bearing.  Cold grease to start with. It heats up and stops lubricating.

 

Roger

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9 hours ago, RogerH said:

Hi Rob,

             is the above immediately after a run - within a couple of minutes.  If not then go for a run. Get the noise and then stop, jack it up and test the wheel.

It could be a wheel bearing.  Cold grease to start with. It heats up and stops lubricating.

 

Roger

My thoughts too.

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Had the same trouble on an Allard.Ended up as a worn bearing allowing

too much end float on the half shaft and hub once things had warmed up

allowing the brake drum to rub on the side of the shoes.

Check for witness marks is all you can do.

Good luck.

Roger M-E

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Thanks for your replies chaps. I hope to get out today and check the wheel and drum once I here the noise. Could well be a wheel bearing - might just change it anyway.

Thanks again

Rob

 

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Hi Rob,

     if it is a rear wheel bearing consider a new hub (not refurb'd) rather than mess around with bearings.

The stub axle could be up to 50 years old and ready to part company.

I have two Moss hubs. They have run well for nearly two years to date.

 

Roger 

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11 minutes ago, RogerH said:

Hi Rob,

     if it is a rear wheel bearing consider a new hub (not refurb'd) rather than mess around with bearings.

The stub axle could be up to 50 years old and ready to part company.

I have two Moss hubs. They have run well for nearly two years to date.

 

Roger 

Roger its a TR3 so not applicable.

Stuart.

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I had the same problem myself for a long time. I did have a thread on here years ago.  My answer at the time was during one week end ,in the Cotswolds, I ran the car for six miles slowly with the handbrake slightly on. It got very hot.This made a difference but not significantly. I loosened the adjuster by two turns and it was fine but not much handbrake. I had my local welder lengthen the handbrake lever by about 1/2" to give greater travel. It is more or less all right now but not as safe as I would like.

I have often noticed in the ST workshop manual, that the 10"Girling back brake linings do not fully cover the shoe. I am always planning to get the angle grinder out and trim back my linings. But there always seems to be something more important to be getting on with.

I am hoping that we find an answer on this thread.

Richard & B

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Had a similar problem with my 3a and it was due to a minimal adjustment to the master cylinder brake rod to pedal. It was not fully releasing the pressure fully through the master cylinder. As the brakes heated up so they started to bind. Heat expands so the situation gets worse.

Worth backing off slightly to rule this issue out.

Rod

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+1 Free play perhaps not adjusted correctly and as Rod describes as it gets hotter it gets worse.

Iain

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Hello Rod & Iain

I had thought of this and had ensured the M/C brake rod was backed off sufficiently. It was a bit tight and I initially thought I may have found the problem, but alas no. I missed it out in my list of things I'd already done, but thanks again.

I've ordered a wheel bearing kit as I've convinced myself it's the problem, having done everything possible with the brakes - most jobs a few times.

Rob 

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21 hours ago, Rodbr said:

Had a similar problem with my 3a and it was due to a minimal adjustment to the master cylinder brake rod to pedal. It was not fully releasing the pressure fully through the master cylinder. As the brakes heated up so they started to bind. Heat expands so the situation gets worse.

Worth backing off slightly to rule this issue out.

Rod

That would cause binding on all four not just one.

Stuart.

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Check the back plate on that side for a groove where the handbrake lever pivots as it can make the cylinder catch at that point and not slide properly when hot.Its easily welded up and ground back flat.

Stuart.

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Stuart, 

That really does sound like a good answer. When it gets warmer I will have the back plate out for inspection. What do you think about the lining not covering the entire shoe as shown in the catalogue ?

Richard & B

Edited by Richardtr3a

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1 hour ago, Richardtr3a said:

Stuart, 

That really does sound like a good answer. When it gets warmer I will have the back plate out for inspection. What do you think about the lining not covering the entire shoe as shown in the catalogue ?

Richard & B

Shouldnt really make that much difference I wouldnt have thought unless the base section is incorrect and too wide for the application but in that case they would hit the drum and there would be a groove round the inner face, are they bought in repro items or been relined locally?

Stuart.

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6 hours ago, stuart said:

Check the back plate on that side for a groove where the handbrake lever pivots as it can make the cylinder catch at that point and not slide properly when hot.Its easily welded up and ground back flat.

Stuart.

+1

Peter W

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Hi,

I a reading this thread more carefully now. I have a Service Instruction Manual no.502602. The Girling brakes are shown on page 4 of the TR3 supplement Brakes. This drawing is also reproduced in the Autopress Workshop Manual by Kenneth Ball.page 107.

This shows the lining on the rear brake shoes does not cover the entire length of the shoe. It is about 1 " short at the end by the cylinder piston for the top shoe and about the same 1" short on the lower shoe at the adjuster end. Moss Catalogue shows a different orientation. At the moment I am not sure which way mine is  installed.

Update; My adjuster is at about 10.00 o'clock and the cylinder is at 4.00 o'clock on the LHS.  The handbrake cable has a clear run to the pivot so it looks correct. 

The linings have been a worry for well over 10 years. If there is any help on the forum I would be very pleased. Meanwhile I will strip out the backplate and make sure it is flat. This seems to be a logical answer. But not until I have fitted the new steering.:(

Richard & B

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This thread has gone very quiet. I am sure that someone has noticed the drawing in the ST manual. 

Maybe it has become a bit boring for the forum ?  Let me know :unsure:

Richard

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Hello Chaps

Just an update on the rubbing noise from the rear N/S brake.

In my last post on this topic I said I would be changing the wheel bearing having convinced myself it was the culprit. I have changed it (but see below) and taken the TR for a spin this afternoon around the Gower. Good news, no noise from the N/S wheel at anytime during a 20 mile trip. So hopefully the problem is sorted. When doing the job and taken off the drum, I noticed that the outer edge at the corner of each brake shoe had been rubbing the inner face of the drum. Some minute metal filings were at the bottom of the drum. This must have been the noise, but caused by a worn wheel bearing giving too much end float? Just my un-educated guess.

I bought myself a hub puller to get the hub off the half shaft. One of those pullers that go over the wheel studs with a centre bolt which you tighten into the end of the half shaft. I needn't have bothered, it didn't move it despite using a breaker bar to tighten it. Fortunately, a mechanic friend of mine has a hydraulic press in his garage so I took the complete half shaft assembly to him. After some considerable pressure via the press, the hub came off with a bang and I mean bang, that's how tight it was. He also pulled off the old bearing- inner and outer races plus the outer oil seal and installed the new bearings and oil seal together with the hub. All I had to do was reassemble it on the car. I was pleasantly surprised how easily the half shaft came out of the diff and even more relieved how easy it was to get back in. Changing wheel bearings for the home mechanic without the right tools is not feasible. Take the assembly off -yes, but then arrange with a garage to dismantle and assemble.

Rob

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Roger

I don't have the tool to set it, so it's suck it and see!

Rob

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