Brakes and mechanics

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stuart_hedges
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Brakes and mechanics

Post by stuart_hedges » Mon Feb 20, 2006 2:02 pm

I can't remember if I mentioned it on here or not, but I spent £120 on getting new pads and discs fitted to the front of my BX about three weeks ago.

On Friday night, on my regular trip down to see my girlfriend in Brighton, I was slowing down for a roundabout when there was a puff of smoke from under one of the front wheelarches, followed by a burning smell. I pulled over sharpish and called for a tow.

The recovery diver agreed with me that it was certainly the brakes at fault; he said that burning smell was very characteristic of overheated brake pads. We decided that that one brake must be binding on; but not enough to prevent the car being pushed by one hand. Also, it hadn't affected the car's handling at all.

Even so, he didn't want to take the risk of telling me to carry on so he took me home and I got the train to Brighton.

I have done a good few hundred miles without problems since the work was done, so bad workmanship on the new pads and discs seems unlikely... or does it? What do you think?

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Post by jeremy » Mon Feb 20, 2006 2:20 pm

there are a number of possible causes - firstly are the pads moving freely or is there a build up of dirt and rust along the edges of the calipers meaning they don't retract properly? Do the calipers slide freely on their runners or, as is common, have they got sticky or stiff? (BX use a single piston sliding caliper on the front - when it gets stiff one pad wears more than the other)

Tthe other possibility is the handbrake - the cable may have been adjusted wrongly, it may have adjusted itself tigheter than usual especially if the operating arm on the caliper was moved back to the end of its travel during the pad fitting, or the cable may be failing and not releasing properly.

Finally - it might be the pads bedding in or even burning off some rust preservative from the new disc that should have been washed off during fitting.

jeremy

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stuart_hedges
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Post by stuart_hedges » Mon Feb 20, 2006 2:25 pm

Hi Jeremy,

I haven't been able to get the wheel off and have a look yet but I will check these possibilities out this evening.

Now that you mention it, the handbrake is a LOT tighter than it was before - I'll check that before I do anything else!

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Post by Stewart (oily!) » Mon Feb 20, 2006 5:44 pm

£120 for disc sand pads, Im in the wrong job again :? Did that include parts?
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Post by AlanS » Mon Feb 20, 2006 9:32 pm

Stewart (oily!) wrote:£120 for disc sand pads, Im in the wrong job again :? Did that include parts?
Stewart
Just as well you don't live out here; you could multiply that by 3 and then ad labour to get a ball park figure.
Yep, just did a quick guesstimate and it would cost almost A$540 for parts alone and they'd charge you at least another $120 for labour.
Scarey hey??:shock: :shock: :twisted:


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Post by Way2go » Mon Feb 20, 2006 10:14 pm

Stewart (oily!) wrote:£120 for disc sand pads, Im in the wrong job again :? Did that include parts?
Stewart
Sure hope so :shock: Had to do that job for the last MOT and new parts bought from GSF; Discs @ £19/pr, Pads @ £10 for 2pr and Brake Cleaner aerosol @ £3.39 = £32.39 + vat :) Job Done!

As you don't need to remove the calipers or bleed the brakes a garage presumably only needs an hour a side, give or take, that still leaves £87.61 for 2 hours work. :evil:
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stuart_hedges
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Post by stuart_hedges » Tue Feb 21, 2006 9:30 am

I haven't got the receipt to hand so can't tell you exactly, but I do remember it was half and half - 60 for parts and 60 for labour.

It's annoying because it's the kind of job I'd usually do myself, but I just don't have anywhere to work at the moment. I live in a terraced house on a very narrow street :(

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Post by AlanS » Tue Feb 21, 2006 10:50 am

stuart_hedges wrote:I haven't got the receipt to hand so can't tell you exactly, but I do remember it was half and half - 60 for parts and 60 for labour.

It's annoying because it's the kind of job I'd usually do myself, but I just don't have anywhere to work at the moment. I live in a terraced house on a very narrow street :(
If you work quick enough, that shouldn't be a problem. :shock: :shock: :shock: :roll: :wink:


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stuart_hedges
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Post by stuart_hedges » Tue Feb 21, 2006 3:40 pm

Forgot to say... when I took the car back to the garage this morning I mentioned Jeremy's points in the first reply of the thread, emphasising the handbrake one as the lever is a lot stiffer and lower than it was before the work.

The mechanic said "We wouldn't normally adjust the handbrake when replacing pads and discs."

Oh really?

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Post by Way2go » Tue Feb 21, 2006 4:13 pm

stuart_hedges wrote:The mechanic said "We wouldn't normally adjust the handbrake when replacing pads and discs."

Oh really?
Hi Stewart, actually this is true as the the calipers and handbrake are self adjusting. So if the cables are OK and there was not a problem before then changing disks and pads should not upset the handbrake.
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Post by ken newbold » Tue Feb 21, 2006 5:03 pm

Stuart, I'd keep an eye on the situation if I were you. Once overheated, the seals in the caliper can become baked and hard, allowing fliud to pass.

Also another point worth noting, if the flexible hose is internally damaged, the brakes will come on but may not go off, as the hose may suck flat inside when you take your foot off the pedal, rare but it does happen.

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Post by Stewart (oily!) » Tue Feb 21, 2006 5:17 pm

I have seen an internally collapsing brake hose, the owner was totally perplexed, the brake could be bled but upon driving it stayed on quite hard, the pads sort of melted, the disc turned blue, in the dark it glowed, owner replaces disc, caliper and pads only to get exactly the same fault!
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Post by Way2go » Tue Feb 21, 2006 5:31 pm

ken newbold wrote:Once overheated, the seals in the caliper can become baked and hard, allowing fliud to pass.
Ken, That's interesting! Could explain Stuart's Puff of Smoke from LHM going onto a hot disc rather than say drifting smoke from the disc overheating the hub bearing.
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Post by jeremy » Tue Feb 21, 2006 5:32 pm

Way - yes you're right BUT - often you find when you look at the brake that the handbrake operating lever on the caliper can be pushed back a little more and this sometimes seems to tighten the adjustment. Whats happening is that the return spring isn't quite strong enough to pull the mechanism/cable back as far as it can go, and so when its helped (as I would do when changing pads) it takes a better bite as it were.

It'll settle down quickly if this does happen - and then be untraceable!

jeremy

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Post by stuart_hedges » Wed Feb 22, 2006 10:25 am

Interesting stuff guys - I'll be keeping an eye on it anyway because we all know these irritating intermittent faults never go away!

I picked the car up from the garage this morning and their report was this: The brake wasn't binding at all when it was in the garage so they can't promise to have fixed it, but they did spot a difference between the affected side and the other and have sorted that.

Apparently there should be a bracket on the strut which holds the handbrake cable and brake flexi-hose in place. This was missing and the cable and hose were held in place with cable-ties. The cable wasn't at the same angle as on the good side, so the mechanic wondered if that misalignment was causing the handbrake to stick on.

He couldn't source the bracket and didn't fancy welding to the fluid-filled strut, so he's bodged something up (I haven't looked yet) to hold the cable at the same angle as on the good side.

So... does anyone know if I can get hold of this mysterious bracket? Or does it come as part of the strut? They creak a little anyway so are on the agenda for replacing - I might just hurry that job up a little (especially if I get my long-promised payrise).