pad wear

JohnT · Unread post by **JohnT** » 03 May 2005, 13:36

I would not recommend saving and re using old pads under any circumstances. For the cost of new sets (£20-)it is unwise to try and make do.If you have any doubts about the integrity of the discs, change them. After market discs are not expensive.

arry_b · Unread post by **arry_b** » 03 May 2005, 14:00

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by JohnT

After market discs are not expensive.
<hr height="1" noshade id="quote"></blockquote id="quote">
Or, as a rule of thumb, very good.

ItDontGo · Unread post by **ItDontGo** » 03 May 2005, 14:27

The force applied to both pads during braking will almost definately be the same whether there is a slight tendency for the guides to stick or not. This is because the brake disk will bend if it does not have equal pressure on either side of it. Plus the force applied to a brake pad is that high that it would move anything sticky.
Sounds more like one pad is getting very hot which will lead to increased wear rates on just that pad. Slight sticking may keep the pad in contact with the disc during driving heating it up which may be the cause of excess wear. It wont be that one pad presses harder during braking though because that it almost impossible and would cause fatigue in the disc after just a short time.

Kowalski · Unread post by **Kowalski** » 03 May 2005, 14:48

If the slides aren't free, that is exactly what will happen, one pad will press harder than the other. Perhaps the brake disc will flex, it takes force to flex it, and that force has to come from somewhere, i.e. from one pad pushing harder than the other.
I've seen stuck calipers where one side of the brake disc was shiny and the other side rusty.

goldfinche · Unread post by **goldfinche** » 03 May 2005, 15:15

Hello this may be ever so slightly off topic because its just happened to my BX. The calipers were badly worn, slides so much that there was no chance that they were sticking, the thud that happened when braking and the feeling that something was about to break was not good. Frightened the bank and got a set of recon calipers (16 V) The nearside caliper would not slide easilly, to cut a long story short the hub was bent I had had wheel bearings pressed in and the caliper mounting lugs were misalined so when the bolts were torqued up they pulled the slides out of alinement.With the worn calipers there was not a problem.
Could the problem be that the hub, for whatever reason,be out of tolerance?? I may be talking a load of rubbish because I havnt seen a Xantia caliper but am assuming they are something of the same kind.
Thank you.
Cheers
Geoff.

ItDontGo · Unread post by **ItDontGo** » 03 May 2005, 15:31

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Kowalski

If the slides aren't free, that is exactly what will happen, one pad will press harder than the other. Perhaps the brake disc will flex, it takes force to flex it, and that force has to come from somewhere, i.e. from one pad pushing harder than the other.
I've seen stuck calipers where one side of the brake disc was shiny and the other side rusty.
<hr height="1" noshade id="quote"></blockquote id="quote">
But you can still push them back by hand no doubts even though the thousands of pounds of hydraulic pressure cant budge it.

Kowalski · Unread post by **Kowalski** » 03 May 2005, 16:04

When my calipers have been sticky, you could slide them freely when there is no load on them, but once they start braking the car the load comes on to them and they stick. I think some of this is down to the fact that the slide is not concentric to the piston, so the slide not only has to slide but it has to keep the caliper parallel to the disc when the forces being applied to it are trying to take it out of true. If you've tried pressing in (or out) an wheel bearing you'll know how easy it is to get them to jam solid if you don't keep them absolutely straight, if your pads aren't absolutely flat and parallel, they'll help the caliper jam up on its slides.

rbruce1314 · Unread post by **rbruce1314** » 03 May 2005, 19:27

Adrian is right- it just HAPPENs on Xantias,even from new. Mine was serviced (free) by my main dealer at 20k, (supposedly) yet 300 miles later the padwear light came on. Lo and behold one pad worn right down, the others still with half life on them. I imagine mr.junior technician pulled out one pad and just imagined the others were fine.
(and before anybody asks, I usually get 35-40k from my front pads having once been a bus driver in the days when you were taught to drive properly).

rbruce1314 · Unread post by **rbruce1314** » 03 May 2005, 19:30

when I said adrian I meant Dave (woollard) Sorry Dave!

fastandfurryous · Unread post by **fastandfurryous** » 03 May 2005, 21:21

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by rbruce1314

and before anybody asks, I usually get 35-40k from my front pads <hr height="1" noshade id="quote"></blockquote id="quote">
Indeed. I very rarely wear out a set of pads while I own a car. It was a bit of a surprise recently when the pads on the 405 wore out. With new decent quality ones in there, copper grease in the sliding pins and on the backs of the pads, and a generally good clean up, I don't expect to have to change them again in at least 30k miles, possibly even up to 50k considering the amount of motorway miles I do.
Mind you, I also tend to get similar sorts of miles out of my front tyres. It never ceases to amaze me that some people change their front tyres at less than 30k intervals. Last set I bought new and actually wore out to the TWI's lasted 55k! Rears (changed at the same time) were still going strong having been transfered to another car, with about 80k on them.

simonelsey · Unread post by **simonelsey** » 03 May 2005, 22:17

I have found that on my xsara I have one pad on front wearing out quicker then rest , 3 out of 4 pads on front are ok normal wear , 1 pad will be worn to few mill . . The calipers slide ok . I have never had a car eaten pads the way the xsara does . I belive the Piston is not relising enough, as when driving I can hear a slight scrapping , Cover brakes slighty squeak will go, So belive piston is not releaseing fully once you have finished braking .Also sometimes ,when I stopped for parking go into reverse the drivers side will make a Unbinding noise as pads are released from disc. Hopfully this will help but I am convinced its caused by piston not going back . PS last braked changed done my self and made sure slide bars where cleaned and greased.Also found piston bit tighter then rest to get back , This is not affecting braking as does not pull , been on rollers and braking is good.

BX-Basis · Unread post by **BX-Basis** » 03 May 2005, 23:59

If your Xsara has a GIRLING brake caliper, you will have to change the frame with the sliders where the brake pads are set into. This is a very common problem on all Xsara and Berlingo with the GIRLING brake calipers. Greasing the sliders is of no use as the sleeves where the sliders are sliding in are worn. You won't really see or feel it when dismountiong the brake but at the garage where I'm working we change these frames at least once per week on Berlingos or Xsaras.

citronut · Unread post by **citronut** » 04 May 2005, 02:06

callipers with handbrake self adjusting pistons have one piston inside the other whilst the inside one revolvs as calliper adjusts outside one dose not rotate and apart from the slots used for windeing pistons back in there are two small grooves beside two opposite slots one of whioch when finnished windeing pistons in should be faceing forward ,when fitting new pads disconect cable from calliper winde piston bback fit pads with copper slip on then press brack pedle if not enough hydraulic presure start engine and press pedle again then re/fit cable if lever is partly on this will make brakes drage which could over heet calliper regards malcolm

simonelsey · Unread post by **simonelsey** » 04 May 2005, 13:05

BX Basis , are the girling ones same as Lucas ?? Always confused as can never see references to Girling (I do belive many years ago in UK I have heard it called Lucas Girling.

BX-Basis · Unread post by **BX-Basis** » 04 May 2005, 23:59

Yes, GIRLING and LUCAS are the same. The Citroen part number is 440440 for massive and 440441 for ventilated discs.