Rear brake sticking

When I bought my car the o/s rear caliper was sticking & overheating. I rebuilt it with a kit from Big Red. It was fine for a while, but I have had the car out today & it seemed to be happening again. It felt like it was hanging on when moving slowly in traffic. When I got back, the wheel was hot to touch. The handbrake cable is new & adjusted correctly. I don't use the handbrake when its parked at home. Any suggestions, are refurbished calipers available ?

They used to be available from Brakes International. Same unit as the Front caliper for a Citroen (cant remember the model number).

I have seen this happen in Macon to Stephen's Alp ........ In that case he was able to secure a S/H unit to get him home.
But over the next few days I gave it some thought and came to the conclusion that if that happened to my Alp, I would try this ...... Remove the caliper, and one by one remove the tubular sliders, by removing their dust covers at each end of each slider and withdraw the slider, clean slider and tube it runs in, then lubricate with grease, and REVERSE the slider when putting it back, replace the dust covers. ...... repeat with the other slider.
The theory behind this is that the slider may wear a bit that causes it to jam, by reversing the slider, it will slide on a different surface, and the jamming of the slider will cease.
See pic below ..... top RH diag 88394 ... the sliders are the tubes which fit between dust seals 6.
Its is just a thought. ...... can't promise anything, but worth a try.

And can be done in-situ, so no need to remove any fluid connections which saves bleeding the system too.

That's certainly worth a try John. Thanks.

When I rebuilt the calipers I was very particular in cleaning the pistons, installing new seals & assembling everything carefully, with copperslip on the backs of the pads & the sliders. Its definitely dragging again so that's a good starting point. I'm thinking the other thing might be the handbrake release springs inside the caliper being weak. I don't use it much, but it does get used occasionally.

What we found on Stephen's Alp, was with the car jacked up on offending side ... other side wheels chocked .... wheel off, hand brake off .... when foot brake was applied and released, the disc could not be moved .... tap caliper with small hammer or large spanner, and the disc could be turned....... repeat, and the same thing happened.
You could also try this ... manually moving the caliper hand brake lever to rest position (if it is not there already) to see if this releases the pressure.
It seems to me that if a tap can release the pressure, then it is a straight mechanical "jam" which leads me to think it has something to do with the sliders........ but, of course I may be wrong.

Yeh wot he said .Hit the carrier with a Birmingham spanner

Ok, I followed Johns suggestion. removed the caliper & turned the tubes round.

I took the car out & initially it felt much better. However as the brakes warmed up, the problem returned. I am thinking that either the piston is sticking, or the pads are sticking.

Thanks guys

[mettersl]

Calipiers are Citroen BX fronts...or very close, if you are looking for new mounts. If you have had the Cali per ovehauled, I'd try new sliders and see if that cures it...on the basis of start cheap and easy when chasing a fault .
Let us know what fixes it....

......... or the pads are sticking.

Hi Paul,
Disappointed to hear that the sliders being reversed have not sorted the problem.
I do feel, however it is unlikely that the piston itself is sticking unless you noticed a high degree of corrosion on the piston surface or the bore itself.
The other thing I have noticed is that with the rear of the Alp jacked up, although turning the wheel by hand feels quite free, but with the wheel off, there is a certain amount of resistance when turning the disc by hand. To me this is normal. I think this is to do with the hand brake mechanism. It might be worth comparing the resistance between the two back wheels to see if one is tighter thyan the other.
I note your comment about sticking pads ....... There is a possibility of this happening.
If you refer to the pic below .... 88311 ..... the "V" casting running right towards 4 o'clock from bolt 3 .... that should be paint free and clear of any rust .... I usually wire brush it if I remove the pads .... and it should be lightly greased as when the brake is applied, the pads come together sliding towards each other along that "V" section ... so to speak, and return when pressure is released. Obviously the movement is small, but as the pads wear, their contact points move along the section towards each other.
Now pic 88337 ..... The wedge "1" , again this is the lower bearing surface for the pads ... so the same sliding principal applies.
Once again the surfaces that the wedge slides along when installing it, again must be paint and rust free and lightly greased.
When installing the wedge, if everything is clean and greased, you should be able to slide the wedge in by hand ..... you should not have to use a hammer or drift ..... you are looking for a sliding fit not an interference fit. You may have to tap the rear edge of the pads to centralise them when fitting the wedge, If you do have to use something to insert the wedge .... it is too tight.
Effectively between the "V" section at the top, and the wedge at the bottom of the caliper, they are acting in the same way as the sliders which both allow the pads to compress the disc and release. Either of these sticking can cause the pads not to clear the disc properly.
I hope this is of help to you.

Hi John

Thanks again for your thoughts.

I have had another look at the caliper today. When I rebuilt it, I removed it from the car. I took it apart completely & reassembled it carefully. I cleaned the piston with fine grade emory, & cleaned out the guides for the pads. I fitted all new seals, & pads, as well as new discs. I also cleaned up the carrier. That's why its puzzling me.

Anyway, I have decided to take Metters advice & I have ordered some new sliders. Citroen BX, cheap on eBay, http://www.ebay.com/itm/CITROEN-BX-ALL- ... 35e11f35f1

I don't know if it will fix the problem, but it has to be worth a try. If only to eliminate one more thing.

Oh btw, I called in at my local Eurocarparts. They would have to do a special order which would take a week & the cost - £41 plus VAT - eeek !

Ok so the new sliders arrived today & I got them fitted. Easy seeing that the caliper had been off recently. The new sliders are exactly the same as the originals, despite being listed as Citroen BX. The kit also came with new dust seals & a sachet of grease.

I took the car out for a brief spin & it seemed better. The wheel centre was not hot when I returned, although it will need an extended run to make sure that the problem is solved.

Heres hoping

For what it's worth.
I've experience sticking rear calipers off and on ever since I owned my GTA.
The process I go through is, remove pads, retract pistons, refit pads and 9/10 it cures it.
On the occasions where that doesn't solve the issue, I then fit new pads - which causes the piston to have a different position in the caliper pot. Bit of an expensive way of 'masking' the issue, which I guess is to send them off the RedX for a refurb.

IMG_3143.JPG

An update,

Thought I had solved the problem, but after a decent run, the problem returned.

I removed the caliper & gave it a thorough inspection. I had replaced everything : new seals, new sliders etc. The only thing left was the piston, which I had removed to fit the new seals. I had cleaned up the end that contacted the pads, but to be fair, it was still pitted. The photo makes it look worse than it was . I decided to replace the piston. Citroen BX front calipers are the same, although they use a different seal. I found a new piston on Ebay for £25 so decided to give it a try. The GTA seals fit perfectly & the problem now seems solved. Having said that, I decided not to adjust the handbrake to far. I have left 8 or 9 clicks on the lever.

Hopefully its now sorted