Handbrake Adjustment

Post by **alainmoran** » Sun Oct 07, 2007 10:56 pm

I've been tearing my hair out over this for a while, it 'should' be easy enough but I just cant quite get it sorted.

I disconnect the handbrake cables at the pistons, adjust the brakes so that they hold nicely with the footpedal, then reconnect the handbrake cables adjust a bit, pull up 3 clicks, check the handbrake is holding (repeat until I cant turn the chuffer by hand) and all 'should' be fine.

However when I then go to re-test the footbrake one side is no-longer working fully!

I've rebuilt both pistons, lubricated the cables and pulled them back & forth to check they are free, everything seems fine .. but for some reason I cant get both the handbrake and footbrake to work at the same time.

Any ideas? Could it be my bleeding? (I've only got me to work on it, so I have to bleed the brakes using a split tube attached to the end of the pipe and stuffed into an old water bottle half full of fluid)

The brakes dont seem spongy on first press though.

Post by **MoggyTech** » Mon Oct 08, 2007 2:06 am

Don't know why you would want to disconnect the handbrake cables to adjust the brakes, but anyway.

Sounds like the cables are not at equal tension.

1: Adjust snail cams to lock wheel, backoff one notch (Handbrake off)
2: Apply handbrake three notches, and adjust cables until you can just get the wheel to move by hand

Done.

Oh and if you have a servo, make sure the check valve is the correct way round

Post by **bmcecosse** » Mon Oct 08, 2007 10:42 am

Sounds like a problem in the cylinder - better open it up and check again. You need to take the handbrake lever out to get at the inner (foot brake) piston - my guess is this is seized. Certainly nothing to do with bleeding. You are right to take the cables off when starting 'afresh' - and if everything is moving as it should - then the handbrake will lock both wheels at 10 mph. Are you sure the shoes are on right way round - actually i don't think they can be wrong on a Minior - it's Minis where are often wrong way! Final slightly desperate suggestion is - there are different bore rear cylinders available - are both your's the same bore?

Post by **kennatt** » Mon Oct 08, 2007 12:53 pm

are you saying that with the handbrake dis connected that both rear footbrakes work,but that when you connect the handbrake ,both handbrakes work but only one side rear footbrake now works. If so cant see how that is possible. The piston in the rear cylinder is slotted to cater for the handbrake actuating lever. If the rear brakes work ok then the piston is free. If both handbrakes work then the lever is free in the piston slot so should work. When you pull the handbrake,the lever moves the cylinder piston to activate the brake.They both rely on each other to work so if one works then they both must work.The common fault is where the piston corrodes inside the bore and stops both that side foot and handbrake from working,because the handbrake lever moves but can't move the stuck piston. As said can't see how the fault you describe can be possible

Post by **alainmoran** » Mon Oct 08, 2007 5:05 pm

With the handbrake disconnected (or slackened off completely) then both rear brakes work correctly. (NB: I removed the cables to be 1000% sure that I was getting the first stage right - aka adjusting the snail cams)

However when I tension up the handbrake cable the offside brake works correctly as does the handbrake, however the nearside never really gets to full (hand or foot) braking with the two cables being of similar tension (measured both by pulling on them sideways as well as looking from the rear at the extension of the arm from the piston with the brake applied)

I have stripped and rebuilt both cylinders including fitting new seals as an attempt to resolve this, however all that seemed to do was make the footbrake more effective with the handbrake disconnected.

Both cylinders appear to be exactly the same, so it shouldnt be a bore problem. One cylinder was a little corroded internally which I lifted off by very lightly stroking it with a fine-grade wet-or-dry glasspaper.

I have also re-greased the cables and pulled them back and forth manually to ensure that they were free in their sleeves (the nearside was originally a little less free than the offside)

I have also replaced the shoes and springs (the front original spring being a little more corroded than one I had lying around)

I should probably also add that the nearside (the one which isnt working right) also binds a little when the handbrake is adjusted to a point where it has any effect.

Post by **Orkney** » Mon Oct 08, 2007 5:44 pm

Sounds like its not sliding up and down in the slot then - does it freely? excellent use for copper grease there BTW

Post by **alainmoran** » Mon Oct 08, 2007 7:06 pm

Heh, I think thats about the only spot I havent copper-eased .. lol

I'll give that a try, thanks

Post by **Orkney** » Mon Oct 08, 2007 7:36 pm

You might want to to take the cylinder out completely and give it a good clean then copper grease - a pain but worth doing.
Whilst your there blow a fiver on a pair of new rubber booties to keep the crud out - money well spent that is.

Post by **bmcecosse** » Mon Oct 08, 2007 8:24 pm

Could be the handbrake lever is somehow jamming the inner (hydraulic) piston from moving when it's connected to the cable. Seems unlikely - but can't see anything else fits the symptoms. You could try swapping cylinders from side to side - but for all it costs - maybe better to just buy a new cylinder and be done with it!"

Post by **alainmoran** » Mon Oct 08, 2007 10:58 pm

cylinders have been completely out, cleaned, seals replaced, backing plate cleaned and then re-assembled .. also replaced the rear brake hoses since I buggered the old ones getting the cylinders off (well I knew I had a new set lying about - heh I have enough bits to make at least one complete car lying about in the garage)

Post by **bmcecosse** » Mon Oct 08, 2007 11:06 pm

Can only think it is something to do with the relationship between the two pistons in the cylinder and the handbrake lever. New cylinder seems to be the way to go.

Post by **kennatt** » Tue Oct 09, 2007 8:37 am

just a thought if the slot in the piston and lever arm has worn so that there is excessive clearance between the arm and the piston when you adjust the handbrake to get a reasonable brake could that be lifting the piston so increasing the size of the bore.Therefore the distance the piston has to travel is increased ,similar effect of badly adjusted foot brake,too much travel to push the linings onto the drum hard enough to get a foot brake can't think of anything else

Post by **RogerRust** » Tue Oct 09, 2007 8:44 am

Sorry if this a stupid comment.

BUT I can't see any reference to how you are adjusting the hand brake. You are doing it inside the car at the back of the handbrake lever and NOT at the snail adjusters in the brakes??

Post by **moggiemadman** » Tue Oct 09, 2007 9:16 am

Arnt you adjusting the cable?
If you want to adjust the brakes look on the back drums and theres a hole turn the drum until you see the screw,then turn the screw and knock your drum off and then you can adjust the brakes? i think thats right.thats how i remember doing mine!

Cheers
John

Post by **bmcecosse** » Tue Oct 09, 2007 10:58 am

Err - yes - the snail (through the hole) adjusts the shoes - but if the hand brake lever is then excessive movement it must be tightened at the lever. However - very important when fitting new parts to slacken off, then reset the brakes at the shoes and then bring the cables up at the lever. While these parts remain in the brakes there will then be no need to touch the cables again.

Post by **leyther8008** » Tue Oct 09, 2007 4:24 pm

The link bar in the handbrake isnt moving is it and giving a bias to one side?