Technical Rear brake not adjusting.

[rizzo360]

Hi Guys,
I have a 500 F with 126 rear brakes fitted having probs adjusting them. My back brake are not working. I can lever the shoe's out but they spring back into the centre, is my top spring to heavy. TIA

 

[The Whitakers]

What you need to do is go backwards as fast as you can and hit the brakes a few times...………..

 

[rizzo360]

Tried that already no luck. Read somwhere the top springs needs wee bit of tension relesed by stretching. Can anyone confirm plz.


Cheers

 

[the hobbler]

The answer to your question is "yes". Basically there are 3 problems with the 'pattern' brake parts for the 126 (500 brake shoes, made to the original 'factory' specification, made by Ferodo can be obtained form Middle Barton Garage)--(1) the lining material is fractionally thinner than original specs, (2) the friction washers on the 'self-adjusters' don't seem to have the same amount of grip that the originals had and, (3) the 'pattern' springs are slightly too short.
The answers to these problems are:--(1) use the best quality shoes that you can obtain--I use shoes made by "Metelli" with no problems, (2) the good quality shoes seem to have better friction washers and, (3) if possible, use the original 'factory' springs. If you can't, then stretch the 'pattern'springs by (if my memory serves me right) about 1/8th inch. If you have the 'factory' springs but don't wish/can't use them, stretch the new springs to match the length of the originals.
The problem is that the new springs, being shorter, are stretched more when you put your foot on the brake pedal and therefore put more 'return' tension into the spring. Couple this with slightly less 'grippy' friction washers and thinner linings and you have a brake operation problem

 

[the hobbler]

Just had a thought---you mention that you have "126 rear brakes"---does that mean that you have disc front brakes? If you DO have disc front brakes, what master cylinder are you using? If you are using the original 'single-circuit' master cylinder (which is quite capable of doing the job) you may find that you have to fit the smallest rear wheel cylinders available (5/8in?). This is because the front calipers use a bigger percentage of the available fluid when the brake pedal is depressed. When I fitted disc brakes to the front of my 500 (126 hubs all the way round) I had great trouble in getting a decent brake 'pedal' until I fitted the small wheel-cylinders to the rear brakes---I now have no braking problem!