Spitfire, rear brakes imbalanced across axle

[David McHugh]

Hi Guys, my Spitfire IV failed it's MOT, one of the things is "Brakes imbalanced across an axle rear" can anyone please tell me what, apart from a faulty cylinder, would cause unequal braking pressure between the back Wheels?

If it is a cylinder is it likely to be obvious which one it is or for the sake of £10 is it just best to change both?

 

Thank you in advance for your help.

 

David

[Pete Lewis]

yes its easy to have the  rear  shoe  fitted upside down. the front one is controlled by the handbrake lever  .

as both shoes are the same the rearmost must have the  square handbrake lever hole at the bottom

 

also disconnect the hand brake cable from the back plate, have the wheels supported when jacked not left hanging. 

now wind the adjuster in firmly till it realy locks the wheels , adjuste the brake cable to be a nice ,but not taut fit to align the clevis pins 

then de adjust the brake till its free   about 4 clicks ( one turn)   then remove the jack

if you leave the wheels hanging you get a false result

Pete

[AidanT]

If you find its a cylinder then do change both. When did you last bleed the brakes? I had a fluid flow issue with my offside rear but was able to clear it by removing the flex pipe and pumping the brakes with a couple of refills of the master cylinder

 

 

Aidan

[Clive]

Possible causes:

2 different sized wheel cylinders

a wheel cylinder piston sticking

Wheel cylinders not moving freely on the backplate

internally damaged brake hose

poor adjustment

worn or contaminated brake shoes

 

But my first job would be to get both rear wheels off, drums off and have a look. It won't take long to check most of that......

If cylinders being replaced, and you have a short pipe connecting the flexi to the cylinder (late mkIV and 1500 spit IIRC) then there is a fair chance the pipe will be damaged undoing it. Be warned!

Most issues are solved by cleaning the sliding surfaces and a smear of copper grease. And then correctly adjusting the shoes. 

[dougbgt6]

I have "self adjusting" rear brakes, another dodgy Triumph design! One side works one side doesn't. The self adjusting "levers" get bent and impossible to reshape. This time around MOT advisory said, "rear brake imbalance on the limit". So it's drums off and adjust by hand. On the upside having to do this every couple of years ensures the wheel slave cylinders and Clive's other points are up to scratch.

[Clive]

On that note....

I recently fitted a sprint axle to my Toledo. That uses "self adjusters"

The axle came without anything inside the drums, and it was tricky getting all the bits, well the adjusters. I carefully cleaned and lubricated them, and for good measure drilled the drum so I can access the mechanism.

 

so far I have been pleasantly surprised that it all works as it should. However, I just wish TR4 stuff was more available at sensible prices (straight swap with manual adjusters)