brakes binding

[alf]

A friend has a problem where his brakes are binding.
prior to a track day last week ( new car) all was fine, but now, the brakes are binding.
He assures me that it is not "nipping up" here and there", it is constantly binding throughout the revolution.


2 things suggested so far.
1/ its down to brake dust. take of the wheels, clean off all the dust etc all will be fine.
2/ he needs to apply copper slip.

question is wher to apply the copper slip.
the brakes binding, must cause a drain on power.

any advice??

[Dave Brand]

Basically it's just a matter of ensuring that everything can move freely. Pads should not be tight in the caliper housing, pins should be free to move & the pistons should move easily. Take the pads out & clean all the mating surfaces,then lightly lubricate them. If that doesn't cure it, you may need to look for hydraulic faults......

[JohnD]

Alf,
You don't say what car.
This is a known fault with Triumphs (yes, those 1960-80s classics - they are raced too, y'know!). Adjust the handbrake cable with the car on jacks, and it tightens as the car comes down and the suspension goes up. No doubt a modern car is better designed, but worth a check.
John

[alf]

oops sorry chaps. its a mk2 xr2 cheers

[Al Weyman]

I had binding recently in my rear calipers and basically they were shot, replaced them with some eBay specials and now perfect.

[R59]

Probably the master cylinder not returning properly, leaving residual pressure in the lines, which increases with each press. Could be caused by adjustment, or foreign material in the cylinder.

[alf]

Originally Posted by racing59

Probably the master cylinder not returning properly, leaving residual pressure in the lines, which increases with each press. Could be caused by adjustment, or foreign material in the cylinder.

if it is down to this would a drain,clean and new fluid do the trick? or is it a seals issue?
cheers so far men

[Al Weyman]

Funny enough my Master cylinder has just gone and blown the seals, just wondering if this may have contributed to the problem.

[Chris Y]

Sounds very much like a fluid return problem that I had. Try removing the reservoir cap, pump the brakes a few times, and see if that helps.

If not, try a full bleed, and if that is difficult, the master cylinder is suspect.

[zefarelly]

I'd say master cylinder return problem as well, I had exactly the same problem with my car when I changed it last year, didn't get past St MArys at Goodwood before I pulled up. we changed the actuator rod over to the original, bled the system through, and I think changed the pads, its been fine ever since.

[R59]

Originally Posted by alf

if it is down to this would a drain,clean and new fluid do the trick? or is it a seals issue?
cheers so far men

Drain it, strip it, clean it, change the seals if they look iffy, check for scores in the bore of the cylinder, put it back together, bleed it, check for a little play in the actuator rod - if there's none, you're in trouble - they'll bind, needs to be "some" play.

I found a load of crud in my rear master cylinder last year, cleaned it out, and it was miles better - previously did 2 laps of Snetterton and had bright red rear discs - horsepower overcame braking effort!!!
When I dipped the clutch just before going into the pit garage, that was it! Stopped! Trolley jack job under the rear axle to move it!

Rob.

[alf]

will try all of that then
cheers
men

[Al Weyman]

Did that cure your sticking rear calipers Rob thats interesting because although I have changed the rear calipers and it is better it still seems one heavy pig to push and I am now wondering if this may be down to the dodgy cylinder.

I have just ordered a new master cylinder from the US today, Wilwood have bought out a nice tandem job with bigger bore that will bolt straight on as I like a servo set up (me old knees play up a bit these days). I was getting to much travel with the standard cylinder anyhow so hopefully this will fix it, just got to wait forever again :-(.

[silver bullet]

alf, I had the same trouble on my mk2 XR2. The problem was sticking pistons, a good clean and a bit of lubrication sorted it out.

[alf]

Originally Posted by silver bullet

alf, I had the same trouble on my mk2 XR2. The problem was sticking pistons, a good clean and a bit of lubrication sorted it out.

cheers
what is the best thing to lubricate with please, ie is copper slippok or a bit to gunky.
I seem to remember stuff called rubber grease in the old days, it was white???
probably vasaline or something, but is there a specific brand to use

[Chris Y]

Alf - something else just crossed my mind.. Which wheels are binding? Fronts or rears, or all of them?

The reason I ask is that some cars with rear drums (Can't remember what an XR2 has right now) have self-adjustment mechanisms. I've seen these seize or fail, and either fail to take up the slack, or take too much slack up. If it's just the rears that are binding, it may well be worth a look at those, before you end up with ther master cyl in millions of pieces on the garage floor, and you're staring at a spring, wondering which end is which

[Al Weyman]

Brake fluid, nothing but!! Don't put grease on them.

[Dave Brand]

Originally Posted by alf

what is the best thing to lubricate with please, ie is copper slippok or a bit to gunky.
I seem to remember stuff called rubber grease in the old days, it was white???
probably vasaline or something, but is there a specific brand to use

Rubber grease is red; it's the only lubricant other than brake fluid which should be used on pistons, rubber boots etc.

Brake grease is white; it's a high melting point grease intended for use anywhere on a brake system where metal-to-metal contact occurs.

CopaSlip & similar products are primarily anti-seize compounds; in effect, ordinary grease loaded with copper powder. However, in recent years they seem to have taken on mystical properties akin to those allegedly possesses by WD40......in both cases, the reality is that they are fine for the limited range of applications for which they were originally intended, but are not a universal panacea.

For lubricating the areas of a brake system where there is metal-to-metal contact, a LIGHT coating of CopaSlip will do the job; but then, so will any normal grease. The key word here is light - you basically just need enough to prevent the surfaces rusting - too much & you risk contamination of the friction faces.

Red & white greases seem virtually unobtainable nowadays - I've got a 500g tin of red grease which I bought to solve a problem on my Mk1 Escort Mexico (it was a current model at the time!) but I can't find white grease anywhere!

[Chris Y]

Originally Posted by Dave Brand

Red & white greases seem virtually unobtainable nowadays - I've got a 500g tin of red grease which I bought to solve a problem on my Mk1 Escort Mexico (it was a current model at the time!) but I can't find white grease anywhere!

And now, a word from our sponsors

Frost ART have the red rubber grease: http://www.frost.co.uk/item_Detail.a...Grease%20(500g)

It may be worth a call to them to see if the white grease is still available anywhere, or if there are alternatives. They're very knowlegeable people, particularly in the traditional restoration and engineering techniques.

Edit: Just noticed that Witham UK have 'white brake grease' : http://www.withamoil.co.uk/qualubeg.html

[R59]

The only white grease I've ever seen is "Water Pump Grease" which is a high temp grease designed for water pump (no, not a Ronseal product!).
It's sticky stuff!!

I agree with Dave Brand, copperslip, copaslip, and other various brand names for copper-laden grease, has been seen by many as the great be-all and end-all of grease lubricants. A bit like lithium based spray greases for everything else (door hinges, steering wheels, roof linings, seats and carpet).
But in the wrong place, like brakes, it's a disaster waiting to happen.

It's a long time since I owned a Fiesta, but I remember the self adjusters on the rear drums, they were a nightmare, but usually they would cause a long pedal, not sticky.

I'd still go for the master cylinder, and that it's not returning properly. In the event though, check the lot, just in case it's a combination of things.

Al - yes I cured mine by fitting a new master cylinder to the rear circuit. I'm considering fitting a larger bore cylinder as with it wound fully front, the rears are still a little fierce, but that could be due to the different types of material in the pads - Hawk HT14 compound on the rears, and Pagid RS29 on the front. The rears are quite agressive on initial bite, but the front's take a little while to warm up. Once they're warm, it's all fine and dandy, but lap 1, and part of lap 2 can be "interesting".

Rob.

[alf]

ta

[Al Weyman]

Surely larger bore cylinder would shift more fluid for a given stroke, do you not mean a smaller diameter one? I have just ordered a larger boore combination cylinder from Wilwood so I hope I am right there as the pedal travel has increased somewhat since I fitted the grand national 6 pot calipers up front and the bigger 4 pots on the back.

[Tim Falce]

With a larger bore cylinder you will have less movement at the pedal and need more brake effort to make them work.

[Al Weyman]

Thats what I want, I have a brake booster so no problem. Funny thing though, I just stuck a secondhand standard cylinder on as I am not sure the new one will arrive in time and what do you know, I swear the car has suddenly became lighter (are you reading this EddyV) and easier to push so maybe there was a problem with the master cylinder (well there was, the seals were blown) causing a bit of bind as although it was better with the Bremsport rear calipers it was still a beast of a thing to push. Just need that bigger cylinder now to limit the travel more.

[R59]

As Tim pointed out, a larger bore cylinder means you need more pedal effort for any given pressure in the line, therefore, if you run a bias pedal box, you go for a larger bore cylinder in the rears to decrease the operation at that end and give more bias to the fronts. Therefore I use a Girling .70 in the fronts, and .75 in the rears.

Rob.