coyoteboy
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| posted on 10/10/12 at 09:27 PM |
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Peugeot brakes
Bah, MOT failure on the commuter car today. Rather spectacularly gone down hill in the last 12 months or so, so the list of fails are:
Strut top mounts starting to seize up (both).
Bottom ball joint (bearly loose IMO, but good catch and fair enough).
Front right brake binding (it was, very, but only after I'd replaced all the pads and discs 2 days ago, typically!)
Handbrakes ineffective (No different to the last 4 years, every time it fails, I pointlessly replace something (last year it was a full caliper
rebuild, new discs and pads on both rears), see no difference in force but they accept defeat and pass it anyway).
Peugeot brakes seem to be an issue! On checking through the front calipers there's a hell of a lot of play in one pin on each (top one on one,
bottom on other) but it seems to be the caliper mount that's worn, not the pins, oddly. On the rears - no idea - everything seems to be working
perfectly, handbrake cable pulls the lever on the back of the piston fine but the force is minimal. Pistons are clean and free moving but the discs
pit all the time even in daily use suggesting zero rear braking. AFAIK there's no brake proportioning valve in the car (hoses run to the engine
bay without stopping at any units, so the only place any such biasing could be done is within the EBD/ABS units, if at all.
Anyone any thoughts on cack Pug brakes?
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dhutch
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| posted on 10/10/12 at 09:57 PM |
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Disks on the rear of the curent 306 are cack, and the front drag intermittently, the drums on the previous 306 where much better. That said, its a 12
yo car and the kitcars brakes got a full referb and replace (new slaves, and bigredd calipers up front) when I bought it which the tintop didnt.
Daniel
[Edited on 10/10/2012 by dhutch]
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coyoteboy
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| posted on 10/10/12 at 10:10 PM |
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Yeah, I never found the drums on 205s/306's very good but they're a dozen times better than the discs on the rear 
As I don't know what the correct pin diameter is, I'm going to assume the mounts have worn (the rear sliders are fine so god only knows
why they're so chuff) and replace both, which is still cheaper than new calipers and mounts.
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froggy
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| posted on 10/10/12 at 10:26 PM |
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Wind the pistons back to the stop and slacken the cable adjusters so the arms are fully back . Then wind the piston out until you can just get the
caliper back on with a touch of drag , they might feel tight to you but that's how I set them . A quick drive round to get rid of the drag then
adjust the cable so you have 6 or 7 clicks on the ratchet should work fine .
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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coyoteboy
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| posted on 10/10/12 at 10:29 PM |
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Confused....they're self adjusting calipers are they not?
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froggy
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| posted on 10/10/12 at 10:51 PM |
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No different from "self adjusting "drum brakes , some work well others don't .
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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mcerd1
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| posted on 11/10/12 at 08:28 AM |
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in my experience 'self adjusting' means you have to adjust them yourself
[edit - I don't mean the cables btw, just the self-adjusters always seem to get stuck after a few months on every car I've ever had
)
[Edited on 11/10/2012 by mcerd1]
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owelly
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| posted on 11/10/12 at 09:41 AM |
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As Froggy says and I'll add...folks tend to adjust the handbrake by taking up play in the cable. This doesn't allow the 'self
adjusting' bit to self adjust!
http://www.ppcmag.co.uk
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britishtrident
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| posted on 11/10/12 at 11:49 AM |
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owelly is 100% spot on with that comment.
Getting back to sticking brakes often the cause is the rubber have been exposed to mineral oil -- ie WD40 --- WD40 contains a lot of
kerosene/gas oil like hydrocarbons. Even a very tiny amount of mineral oil will eventually cause the seals to become hard.
In normal operation the piston(s) in a disk brake caliper don't slide in the inner hydraulic instead the rubber seal, the rubber seal distorst
elastically to allow to allow the piston to move, when hydraulic pressure is released the piston is pulled back by the rubber. In effect the
rubber seal acts as the return spring.
Relative sliding movement only occurs between when pad wear is being taken up, so the rubber seal not only acts as a return spring but also as a
self-adjusting mechanism.
When the seals swell and go hard the rubber cannot distort enough to allow for normal movement so the piston slides in the seal and the brakes
sticks on.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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coyoteboy
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| posted on 11/10/12 at 09:10 PM |
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Hang on, there's nothing human adjustable on these calipers guys, you just shove the piston back (ok, wind) in and check the cable lever on the
caliper is retracted when fitting.
As for sticking; the rears are not sticking that I see, the fronts are but they move freely when moved by hand. I think its wear in the caliper mounts
on the front.
Rears had complete strip and rebuild not long ago. Fronts have never been touched other than pads/discs.
[Edited on 11/10/12 by coyoteboy]
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froggy
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| posted on 11/10/12 at 09:18 PM |
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Can't offer any further assistance , I run an mot station and have tested and repaired 1000,s of vehicles with this style of parking brake ,
this is how I do PSA vehicles with this type of caliper .
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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britishtrident
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| posted on 12/10/12 at 07:33 AM |
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If you can wind back the pistons you can wind them back out.
Some times though the only solution is a new caliper or a rebuild.
Rear disc brakes on FWD hatch backs are pretty pointless. on larger models many manufacturers fit drums inside the disc in an effort to give
a decent handbrake.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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froggy
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| posted on 12/10/12 at 08:47 AM |
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No complaints from me , poor car design put my daughter through university  I find that setting the piston so there is a bit of bind against the
disc takes all the compliance out of the floating caliper so the lever puts pressure on as soon as it moves rather than taking the slack up , not a
permanent cure but gets the figures up enough to pass usually I can get them to lock on my rollers
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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coyoteboy
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| posted on 12/10/12 at 04:51 PM |
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BT its an estate, regularly carries heavy loads but yes I agree very little use on a fast hatch, though my old 205 drums used to bite nicely and I
would rather have them! My Celica has drums inside the discs, it bites nicely and never has pitted discs despite the original calipers from 21 year
ago!
I'm going to have to spend more time with that mechanism on the rear. As I say I fully stripped and refurbed the rear calipers replacing
anything it needed (seals, boots etc, piston and sliders were spotless) and the lever mechanism in the back worked fine. If I set it to bite early it
soon re adjusts but I might get it through mot I suppose, fair point. Just baffled as to the repeated corrosion and poor brake despite an apparently
perfectly functional caliper. Never had one like it!
Thanks for the thought folks!
[Edited on 12/10/12 by coyoteboy]
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MikeRJ
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| posted on 12/10/12 at 05:38 PM |
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I'll just say that handbrake cables can be the cause of very poor hand brake performance without being obviously knackered from the outside.
I replaced the ones on my Fiat Coupe (notorious for crap handbrake) and it transformed the handbrake, from being barely able to hold the car on my
driveway to being able to do handbrakes turns with ease in the car park at work The old ones weren't seized either, I could move the inners
by hand pretty easily, but I suspect under tension the friction was increasing to the point that minimal force was being applied to the caliper.
[Edited on 12/10/12 by MikeRJ]
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coyoteboy
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| posted on 17/10/12 at 12:21 PM |
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Further to this, it's quite interesting that the handbrake (all brake) test(s) is(are) entirely subjective. I'm 6ft 1 and fairly meaty, I
could (and have, don't ask!) rip the handbrake lever out of the mounts. The guy who tested it was a weak looking young chap. How is it fair that
his weakness can make the difference between a 15% fail and a 16% pass if his boss was doing the test?
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froggy
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| posted on 17/10/12 at 12:28 PM |
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Would you have been happier if the tester had pulled the lever out of the floor then ?
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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coyoteboy
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| posted on 17/10/12 at 02:04 PM |
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I'd rather they actually tried to pass it. Maybe they need shreddies in the morning.
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coyoteboy
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| posted on 21/10/12 at 11:28 AM |
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Well it passed but I didn't change anything on the handbrake. Wish he was consistently friendly about it.
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