handbrake lever return spring specs?

[Tuga2112]

i had a look at the parts catalog found the code a100j6065s but no details about its specs.

the issue im having is the fact that the ones currently in the car are unable to completely retract the arm, the end result is that the pads automatic adjustment doesnt work, and for the 3rd year in a row i have to manually adjust them to pass the MOT.
they are fairly cheap from SJS so i ordered a pair under the assumption that the ones in the car (even tho they look in pretty good condition) have lost some of their strenght over the past 30 years of being stretched 99% of the time.

i would like to know if anyone knows the specs for the springs, i have a feeling im going to need to buy something stronger anyway

[dapinky]

Joao,

I can't help with the spec of the springs - but I can completely sympathise with your predicament..... My springs are also a little past their best, and every year they get soaked in various chemicals to try to keep them clean and good.

The original ones went in the bin years ago due to the same symptoms you describe (failure to retract the lever), but I had a set from a pair of Dorman calipers and used them.

Whilst the 'main' issue for me is the actual friction between the lever and the calliper putting extra effort on the spring, and no matter how many times i rebuild the calipers, it always degenerates over time.

The best I have achieved with the springs is to soak them (short time) in Hydrochloric Acid at 20% concentration to disolve the rust, followed by a longer dip in Phosphoric Acid to convert any remaining rust to Iron Phosphate.

For the HCl I just use 'standard' brick acid which is available from any builders merchant in a 5L container, and the Phosphoric acid is bought at 81% purity and diluted to about 10%.

For best results, the spring needs to be extended when dipped so the rust between the coils is removed/treated.... but holding it stretched with your fingers isn't an option with HCl!!!! - a piece of wooden batten with a couple of screws in it works well - put it into the tray of HCl and watch it fizz a bit for only as long as it takes to remove the chunky buts of rust. Remove it and wash well in clean water (drop the batten/spring into a big bucket of water and leave it for a good time). then place into the Phosphoric Acid for about half an hour, remove and rince well - and job done!

You will see that the finished article is about 2mm shorter due to the expansion of the rust between the coils - maybe not much, but every little helps.

**** I am aware that the acid dip will change the material structure of the steel spring and potentially make it more brittle, and less 'springy' - but it was done just to see what effect it would have - anyone following this procedure should only do so on spare items which ae considered 'scrap' at the time****.

A better way is to replace them - and a 'shorter' or 'stronger' spring is a good idea, but won't overturn the excessive friction of a rusty caliper lever. (undo the big nut on the back of the lever (11/16", but a 17mm should work), pull it off the square operating bar, clean up the inner face, apply silicone grease and replace).... dont operate the lever whilst the nut is undone without expecting some brake fluid to leak from displaced 'O' rings, and potential requirement for caliper rebuild!!!!

... However, and even better way to solve the problem is to fit a pair of Honda callipers

[RonR]

The SJ springs were man enough when my rear calipers were rebuilt last year.
Aside from Dave's excellent advice, you might like to check the cables for fraying or sticking while you're at it, mine needed some lubrication to run smoothly.