TR3 Rear brakes

[Richardtr3a]

I would be grateful for some help with my very hot brakes.

 

After repeated failure of the rear nearside oil seal I arranged for a new half shaft and 4 new rear linings to be fitted to my 1958 Girling 10" drum rear axle.

 

After collection from the garage I travelled 125 miles before finding out that I had no handbrake. Why should a new half shaft affect the handbrake? I have been attempting repairs ever since.The adjuster is free and there is so little adjustment that the foot pedal has long travel and is not as safe as I would like. The wheel cylinder has a new seal and retaining springs. It moves freely. The return springs are new and the handbrake now has so much travel that it is no use at all.

 

After a four mile drive with no use of the brakes at all the rear drum is too hot to touch. The other side is warm but can be touched easily.

 

I notice that the garage also replaced my hub and that the new one does not have threaded holes for the two small locating screws. I have taken my old half shaft to an engineering shop who have offered to grind and metal spray my old shaft back to original condition. However they are making a fuss about removing the hub. Is this a problem?

 

While I have been working on the brakes I notice also that the two sides seem to have different linings. The hot side has a shorter lining which does not cover the whole shoe. While the good side seems to have a lining which covers the entire surface of the shoe.

 

If anyone can offer me some advice before I approach the garage I would be very grateful. I have spoken to them and they want me to bring it in. But it is a long drive and I want to know what is going on before we start again.

 

Could the fluid be inhibited from returning to the master cylinder by some internal block inside. This would affect the front brakes also.

 

Thank you

 

Richard

[marvmul]

Does that wheel turn freely when the car is jacked up? Did you bleed the brakes?

Perhaps you should compare the brakes shoes thoroughly, also if the extremities are identical (square to the brake cylinder and adjusting mechanism.

Also the diameter of the 2 drums should be the same and the drum should be true, not oval : if a drum is turned out, the diameter is increased. An internally deteriorated rubber brake hose can also cause overheating.

Perhaps you can try and swap the left and right wheel brake shoes?

[Richardtr3a]

Does that wheel turn freely when the car is jacked up? Did you bleed the brakes?

Perhaps you should compare the brakes shoes thoroughly, also if the extremities are identical (square to the brake cylinder and adjusting mechanism.

Also the diameter of the 2 drums should be the same and the drum should be true, not oval : if a drum is turned out, the diameter is increased. An internally deteriorated rubber brake hose can also cause overheating.

Perhaps you can try and swap the left and right wheel brake shoes?

 

 

The wheel turns well and I will have to replace the linings on both sides. How do I check for linings square to the drum. The brake hoses are all stainless steel braided and fairly new. I think my problems began when I left the garage and had no hand brake. There is a mystery in the fitting, because the set up was fine when I took it in and hopeless when I collected the car. The oil seal seems to be holding up. So we are getting forward very slightly at some cost. Thank you for your interest. Richard.

[marvmul]

The lever of the handbrake at the backplate has a little spindle wich is fitted in a groove at the back of the wheel brakecylinder housing : if the lever is not fitted in that groove, the housing is pushed to the outside and you get no handbrake action because the spindle can move around.

The brake shoes should make even cantact with the drum when you hold them against the drum.

It's very well possible that something is fitted wrongly.

[Richardtr3a]

The handbrake lever is fitted correctly and the whle wheel cylinder moves as it should. yours Richard

[Richardtr3a]

I am disappointed that no one has any subtle answers which I have missed. Don Elliot is usually the man for tricky problems. Where are you Don? I will swap the linings over as a diagnostic test and see how we go.

 

I am still concerned over the hub for which I did not request any work, and which was changed anyway. I am looking for an answer before buying any new drums,shoes etc.

 

Thank you so far. Richard

[jean]

IMHO for proper braking both sides should be identical, this with concern to drums and brake shoes.

Did you check if the drums are turning well clear of the shoes, to say they do not touch the drums on the sides and that they are both fitted in the same, correct way . Further you will have to check the axles for correct play, maybe the workshop neglected to shim out the axle when they replaced the hub:(

Jean

[j-eichert]

Hello Richard,

 

having a '59 rear axe in state of re-assembly, I may be able to give some hints.

 

It seems to me, as if the workshop replaced the whole half axle including the rear brake - thats the "easy" job", just 6 bolts (and only once, if you don't check for the play of the rear hub). During this operaton, you have to take care of the brake pipe, rearrange the hand-brake cable and of the rear axle hub's play.

 

1) The TR3- arrangement of the handbrake at the rear axle should be tolernat to any misadjustement on one side. In my eyes, both levers are pulled towards the center of the car by the compensator lever. Any wrong adjustement with one of the two cables will affect the positon of the lever and thus the positon of the handbrake lever -> You have too much or no handbrake. But this should always be symmentrical.

(In theorie! Maybe one of you expierienced guys knows different)

So I would assume, that the adjustement of the rear hand barke cables is gone. But this can be adjusted, the procedure and data is given in the workshop manual.

 

2) Brake linings have to be absolutly identical !

- Braking force is proprotional to contact area and pressure.

So it is obvous, that different linings as you describe them leads to asymmetric brake. And, at last according to the workshop manual, the correct linings do not fully cover the shoe.

One side getting hot lets me assume, that something maybe wrong with pressure to the wheel cylinder or its relief. The cause can probably be found somewhere between T-piece (splitter) on the rear axle an the wheel cylinder. Then, as tere are no flexible hoses, a pipe can be bent, or twisted blocking flow. High braking pressure applied will force brake fluid to pass, but it may not flow back, thus keeping pressure on the wheel cylinder.

 

3) Could the rear axle hub's play be "negative"? If you forget the shims, you can tighten the rear hub. This looks, if you miss below 1/16", as if your play is zero. Resulting in massive pressure on the bearings rollers. The result may be excessive force use up in deformaton of rolers during driving, producing heat, heating up the the bearing -> hub -> brake drum?

There has to be a small play of 1/32" or so, but more than 0,005" (again quoting the manual).

 

Cheers and good luck !

[marvmul]

The play of the hubs is automatically dividid over the 2 sides. Adjusting at one side, automatically changes the play on the other side.

Did you check the adjusting mechanism? If it is stuck, you can't feel if it is in a square position (adjusting is always in steps of 90° because of the shape of the wedge. The wedge moves 2 pieces apart in the adjuster housing. These round pieces can easily fall out when the brake shoes are not in place.

To adjust the brakes you have to screw in these wedges as far as possible (on the back side of the backplates) and release till the wheel is turning almost freely, ideally the two sides need the same number of clicks of 90° (about 3 to 6 clicks or 270 to 540°)

[Don Elliott]

I'm sorry Richard for not commenting. But I have two reasons. 1. - I was away on holiday (I've driven my TR3A 5414 miles so far this summer) and 2. - I've never had this problem. I had a clutch and brake shop bond new linings onto the original shoes at 80,350 miles from new and now have done 92,000 miles on these. I know I have to adjust them a little closer to the drums soon because the hand brake lever comes all the way to the top.

 

Don Elliott, Montreal

[greasemonkey]

By the By .... the way to cure leaking oil seals is to slip a 'Speedi-sleeve' over the shaft so that the oil seal has a nice smooth surface to run on. These sleeves are stocked in all sizes & can generally be bought from your local friendly bearing supplier. They are only a few thou. thick & hence you can still use the standard size oil seal. I did the half shaft a few years ago ... about £20. The fitting tool that comes with it assumes a shaft about 3 inches long!!! So you have to find a length of pipe or whatever to tap the sleeve down towards the hub. Much cheaper & quicker than metal spraying & grinding!!

[Richardtr3a]

By the By .... the way to cure leaking oil seals is to slip a 'Speedi-sleeve' over the shaft so that the oil seal has a nice smooth surface to run on. These sleeves are stocked in all sizes & can generally be bought from your local friendly bearing supplier. They are only a few thou. thick & hence you can still use the standard size oil seal. I did the half shaft a few years ago ... about £20. The fitting tool that comes with it assumes a shaft about 3 inches long!!! So you have to find a length of pipe or whatever to tap the sleeve down towards the hub. Much cheaper & quicker than metal spraying & grinding!!

 

 

This does sound very interesting. I have checked all adjusters and have no handbrake connected. At the time of the original work thehub was changed and the handbrake lost any effective use. So the work done lost the handbrake. Before the garage got there I had a good handbrake. So I feel that this hub is the root of the matter ,so to speak. I think that I will try Speedisleeve and have the old half shaft replaced with the old hub still in place. Firstly I will swop over the shoes from one side to the other as a test.

 

Thank you for your interest.

Richard

 

By the By .... the way to cure leaking oil seals is to slip a 'Speedi-sleeve' over the shaft so that the oil seal has a nice smooth surface to run on. These sleeves are stocked in all sizes & can generally be bought from your local friendly bearing supplier. They are only a few thou. thick & hence you can still use the standard size oil seal. I did the half shaft a few years ago ... about £20. The fitting tool that comes with it assumes a shaft about 3 inches long!!! So you have to find a length of pipe or whatever to tap the sleeve down towards the hub. Much cheaper & quicker than metal spraying & grinding!!

 

 

I am very keen on the speedi sleeve and would be much happier with my original half shaft and hub. Please point me at a supplier, West London preferred.

 

Thank you Richard