getting dangerous- replacement calipers needed.

[tim]

I put a thread on many weeks back about the handbrake on the White One, which was getting progressively poorer. If you look back, you'll see that no-one came up with any solution to the problem and although fitting new discs and pads tightened things up a bit it hasn't cured the problem. It's MOT tomorrow and even if they pass the handbrake, which I suspect they will, the problem will still exist and the car will still be unsafe. So does anyone have a pair of calipers for a 19 TXD they can sell me? Only proviso being they must be in reasonable nick. We salvaged a pair off the scrappy but both bleed nipples will need drilling out and retapping, and one hose is still seized in place. Doable but a lot of work and they are obviously not that sound.
I could still transfer the handbrake components from these into the existing calipers (I have stripped them out and they look fine) but without some guidance as to why the problem exists in the first place, this could be a waste of effort; the car is used every day so any 'downtime' is a pain.
I would stress that the probem is not due to adjustment of cables, sticky pins etc; all that lot is working as it should do. It's a caliper issue of some kind. Has to be. If it isn't, only the fitment of another set of calipers will disprove that..... Malcolm was categoric that you shouldn't take up normal free movement in the cables by means of the threaded adjusters,though this is the only obvious solution. So - if you can spare a caliper or two, please help! (Even the loan of some would do, simple enough to swap 'em over. I could then rebuild the old ones in comfort...)

[Dollywobbler]

At £40 a side, new ones aren't hideously priced. http://www.ebay.co.uk/itm/CITROEN-BX-RI ... 0741093655" onclick="window.open(this.href);return false;

[tim]

Ah ha... I didn 't think they were available, don't know why but definitely had that one in the head for some reason. Thanks for that! Maybe the way to go, though I didn't fancy spending £80 this week on top of the MOT and roadtax. However, if that's what it needs then mustn't grumble too much!
Saves an awful lot of pratting around too. We'll see what the MOT brings. (hydraulic leak somewhere for a start, though the old " just fixed a split hose but there's still a bit of runoff" one should help.) be nice if he could actually find it for me. Up until now, by the time I've got down to Andy's and up on the ramps, the underside is so covered with puddle splash it's difficult to see wtf's going on.

[tim]

I suddenly thought, lets's buy 'em. But I looked again and unless I've missed a bit they are right-hand ONLY. Without a left hander to go with it, one on its own ain't going to do it and I'm not sure how well it would work. With one coming on perfectly surely this would throw all the 'slack' onto the other cable and cause the old caliper to work even worse than before? At the moment the pull is absolutely even and I've just about run out of clicks.

[Vanny]

The hand brake mechanism on these things is basically a camming arrangement. Normally when the handbrake works poorly it is because the cam isn't working right. Ive always found this to be caused by some contamination in the cam it self (usually very old and dry grease), and i've thus far never failed to revive a poor operating hand brake with some through degreasing, serious cleaning and lubing back up.

It is of course possible that the cam is in some way damaged. Does it have good movement with the cable disconnected? The lever arm should rotate almost to touching the cable mount lug.

[tim]

vanny - hi. You gave me some useful ideas in the last thread which was about mid-June (I just looked it up). I would say that you are quite possibly right. The problem I have is that I have to remove the existing calipers and strip them to see what, if anything, is amiss. If there is nothing obvious then I am stuck in that I have to reassemble them and refit them - wasted time and nothing to show for it. Sure, this may yet be the only way out of this one (though I briefly got excited about getting a pair of new 'uns) and I can do it; but I would much. much rather have a replacement pair then I can sit down at the bench and strip down the offending components and fix them at my leisure. Still, this has only being running since 5.00 pm, by bedtime someone may have pointed the way to a left-hand one as well; and I finally got around to setting up an Ebay account., so it's all good....

[citronut]

.. Malcolm was categoric that you shouldn't take up normal free movement in the cables by means of the threaded adjusters,though this is the only obvious solution.

not quite as open and shut as that realy Tim,
what i say is you should after fitting new pads, or retracting the caliper pistons for any reason,
you should firstly and before re/attaching the cable to the lever/arm of the caliper, start the engine and press the pedal 2 or 3 times as this re/sets the hand brake mechanism inside the caliper,
then and only then re/attach the cable and adjust it up by the nuts to take up the slack, but not so much that it pulls the arm in the slightest whilst the hand brake is off/released

regards malcolm

[Vanny]

^ This is what i do.

Normally followed by a session of bleeding the yellow LHM out of the end of the caliper piping. And it's always yellow.

I have on one occasion had to readjust hand brake cables towards the end of a set of pads, but only because the MOT man couldn't get to grips with the idea that they can self adjust and take up the slack!

[Vanny]

Ebay, LHS, ~£80

http://compare.ebay.co.uk/like/27113520 ... sbar&cbt=y" onclick="window.open(this.href);return false;

Ebay LHS ~£65 (reman)

http://www.ebay.co.uk/itm/BRAKE-CALIPER ... 1c28243a6c" onclick="window.open(this.href);return false;

Ebay LHS ~£45
http://www.ebay.co.uk/itm/CITROEN-BX-ES ... 43b789dd08" onclick="window.open(this.href);return false;

There are a hell of a lot of options price wise!

[citronut]

I have on one occasion had to readjust hand brake cables towards the end of a set of pads,

as you probably know adjusting the cables does not put any more load/pressure onto the pads, but just reduces the lever travel only,

but only because the MOT man couldn't get to grips with the idea that they can self adjust and take up the slack!

i find after the MOT tester has done his bit the hand brake has adjusted its self up,

because most MOT testers in the proses of there duties press very hard on the brake pedal,

[tim]

Well..... like I say, if the bugger passed the MOT last year it should go through again. So I'm not fussed about the ticket itself. But it doesn't mean that the handbrake is actually safe.
Malcolm, some crossed wires here. In our last thread I never actually understood that you should do the pedal thing with the cables not yet attached. . The history of this one is that these calipers were a replacement for previous ones and fitted by the local Citroen garage (s/h of course) and they stated that because of the age of them the adjustment was the best they could do. So they were never right. If the garage couldn't do better, then maybe there ain't no better on this setup.
However, I'll do this - not difficult after all. Tomorrow I'll disconnect the cables and try to reset the calipers. If you look back at the old thread you'll remember that I was fishing for an answer as to exactly how these can 'reset' themselves and I am not yet sure how this can happen, as what I see when I handle the parts is a purely mechanical linkage with no obvious scope for resetting. So I'm still not clear why I can't take up the surplus movement on the adjusters.There is, clearly, way too much movement somewhere and I have had had reasonable experience with brakes; I can tell the difference between 'slop' and actual free play. Incidentally, I took particular care to get the gap between pads and disc right as per H****s manual, I found a 1/4 turn of the piston was enough to be too much or too little, and I used a feeler gauge to get the best setting. So I'm convinced that the basic set-up is good and there is a specific problem somewhere. (either the components, or the mechanic, not a lot of slack there really!) Anyway, time for a dog walk, bedtime and more tomorrow.

[Dollywobbler]

Depends what you mean by safe. If you mean to hold it on a hill, then that's not recommended anyway. I never trust a handbrake - especially not a Citroen disc-brake one.

[Geoffrey Gould]

Hi, if I may put my pennyworth in.Wind the pistons Into the caliper as far as they will go, they will be flush with the caliper face. Dont try to adjust the pistons to remove the gap, there will be a large gap. Make sure that the slides are free and the calipers move freely.
Then as above, no cables connected and push the pedal HARD a number of times. Connect cables and adjust.

Have you bled the front brakes, it wouldn't hurt. I have Never had to adjust the pistons to the pads manually.
Good luck.
Geoff.

[citronut]

Hi, if I may put my pennyworth in.Wind the pistons Into the caliper as far as they will go, they will be flush with the caliper face. Dont try to adjust the pistons to remove the gap, there will be a large gap. Make sure that the slides are free and the calipers move freely.
Then as above, no cables connected and push the pedal HARD a number of times. Connect cables and adjust.

Have you bled the front brakes, it wouldn't hurt. I have Never had to adjust the pistons to the pads manually.
Good luck.
Geoff.

yes exactly Geoff,
i will add another halfpence worth

two of the opposite slots in the piston face have a groove beside them these two slots have to end up at a horizontal, and be in a position to allow the pip on the pad against the piton to slide through/into the front most slot,

I was fishing for an answer as to exactly how these can 'reset' themselves and I am not yet sure how this can happen,

these callipers adjust through the pistons being jacked out by hydraulic pressure as you press the pedal,the threaded section wind its way out as the pads wear down,

they dont adjust by actuating the hand brake lever,

regards malcolm

[Vanny]

I was fishing for an answer as to exactly how these can 'reset' themselves and I am not yet sure how this can happen,

these callipers adjust through the pistons being jacked out by hydraulic pressure as you press the pedal, the threaded section winds its way out as the pads wear down

What threaded section? On the piston? Non of the BX front calipers I've ever had wind out.

My understanding is that the cam on the handbrake does the function of the thread on 'normal' calipers of the era, the cam holds the piston out, when you activate the lever you further rotate the cam and thus push the caliper piston that little bit further out, compressing the pads to disc.