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MG MGA - Excessive Brake Pedal Travel

1959 1600. I have too much pedal travel in the brakes, they are working fine but too much travel. I have bled them out after changing the rear slave cylinder seals.

I suspect the problem is the RHS rear, I am unable to adjust the shoes up far enough, the adjuster just goes over the top and back to minimum. I must be missing something but I have compared it to the LHS (which is fine) and it looks identical. The brake shoe condition is fine with plenty of material left.

Does anybody have any ideas?

Thanks

Gordon
Gordon

Gordon,
Is it possible that the brake drum on the RHS has too large of an inside diameter? Have they been machined recently?
George
George

To ensure that the problem is just a fit issue with the shoes and drums, try setting the hand brake ever-so-slightly. The brake pedal travel should be reduced significantly.

If this doesn't help, then the problem lies elsewhere.

Chuck
Chuck Schaefer

Try a small C clamp on each cyl,test your pedal then,then remove one at a time and ck again.Then move to the front brakes and a similar procedure.
wc wolcott

Thanks for your fast response

George - the drums have not been machined recently and the problem has only surfaced since I did the seals.

Chuck - setting the handbrake does have some effect but does not solve the problem entirely, as well as thsi adjuster problem I guess I still have some air in there somewhere.

The strange thing is that I can't make the shoes grip with the adjuster up to the maximum, it is almost as though I has a spacer or something missine but I can't see anything on the other wheel or by stidying the manuals

Gordon

Gordon

what i have found is that when you work on the rear cylinders, they can be full of air, as the bleed screw is lower than the piston. if you take the piston out, you will see the air pocket inside. to fix, take the piston out, pump the brake pedal a small amount till the fluid is at the top of the cylinder, then push the piston in while openeing the bleed valve.
mog

Try switching the rear brake drums to rule out them as the cause of the problem. I would also measure the total length of each cylinder between the brake shoes with the emergency brake off and the adjusters at minimum adjustment. If there is a difference in length, then the problem is with the "shorter" wheel cylinder and probably not with the brake drum. Air in the system should not affect the shoe adjustment.

Good luck in solving this problem and please post the solution when you find it.

Don Carlberg
D. R. Carlberg

Is the wheel cylinder free to slide?
John

Also, when you bleed the system you are to start with the cyl farthest from the master cyl.

On a rhd car you will do it in this order, rhr, lhr, rhf, lhf. to ensure you have removed all the air bubbles from the line..
Chris Hausbeck

chris, it makes no difference if the car is left or right hand drive, as the junction for front and rear is on the top of the right hand frame, ahead of the bulkhead. and the furthest brake is lhr not rhr, so order is lhr, rhr, lhf then rhf.
mog

Thanks MOG,

I stand corrected., Thanks as well as I would have screwed up my bleeding process.

Chris
Chris Hausbeck

Thanks for all your input.

I think I do have some air still in there, I did bleed in the right order but I guess I need to go round again.

But the adjuster problem must be something else. Thanks particularly Don for your input will try those tests in the morning.

Gordon
Gordon

Thanks for all your help and particularly Don who put me on the right track.

I measured the wheel cylinders and sure enough one of them is 1/4 inch shorter than the other. I presume a PO must have changed the RHS cylnder for a non-standard part. It probably adjusted up OK originally but as the shoes have worn down it reached its limit.

I should have noticed when I changed the seals and I do sort of remember thinking there was something odd about them. But there was a time gap over the winter between doing one side and the other and I didn't think too much about it.

That will teach me to be more observant.

Sent off to Moss for a new cylinder and hope it is the right one.

Thanks again for all your support

Gordon
Gordon

Gordon

I have usually found these items readily available from a local motorfactor without having to send away to Moss.

Steve
Steve Gyles

This thread was discussed between 04/05/2006 and 05/05/2006

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