STICKING BRAKES ON FOURTRAK

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I have a proble m that I hope someone can shed some light on. Basically the nearside front brake caliper is sticking and causing the brake to overheat. The caliper has been replaced with new as has the flexi brake hose. THis has not cured the problem. The vehicle is a 92 Fourtrak TDX with leaf spring suspension. Any clues will be gratefully received.

Thanks Phil

sticking brake

Hi Phil,

when the brake is sticking loosen the brake pipe from the N/S/F caliper where it fit into the master cylinder. If the brake the brake frees off then it sounds like the master cylinder might be causing your trouble. (The master cylinder has seperate outlets for each front brake, it is possible that a portion of the seal has become lodged in the feed hole to the n/s/f caliper and is acting as a kind of one-way valve). If the brake is still stuck on try loosening the bleed nipple on the N/S/F caliper, if that frees the brake then it points to your brake pipe (either a kinked metal pipe or collapsed flexy).

If you think it isn't the fluid side then you'll have strip the pads out of the caliper, push the piston back in (on a new caliper you should be able to push it back by hand). Next try the pads in the cailper and in the caliper mounting bracket to make sure they aren't tight anywhere. Then bolt the caliper back on with out the pads to make sure the guide pins slide freely. Obviously anything that is tight or sticking isn't helping.

When you have rebuilt the brakes, press the pedal to pump the pads back against the disc and make sure you have a good solid pedal before you use the car again.

I hope this is some help

STILL STICKING FOURTAK BRAKES

THanks Daz, help and comments much appreciated. We followed your suggestions and everything suggested that the master cylinder was faulty, this was duly replaced with new from Milners. Test driving indicated the problem solved. However, after a trip of 30 miles or so to Garbutts to find some rear light clusters I could feel that the free play on the brake pedalhad disappeared and the pedal pressure was harder. Sure enough, on stopping, the same n/s front caliper was locked and the heat could be felt from 12 inches away. THe o/s felt cool. THe locking of the brake was such that the fourtrak would not free wheel downhill.
After an hour or so looking for parts in the scrappy the brake had cooled and freed itself to allow us to continue on our way. I am at a total loss what can be causing this. THe history is as follows:
-front pads replaced when purchased in Jan, n/s found broken intwo pieces. Rear drums all OK.
-new n/s front caliper.
-new n/s front flexi, o/s front has not been replaced.
-new copper pipes from both flexis to master cylinder.
-all nipples freed and cleaned system fully bled.
-one of the new coppers blew off the nut at the master cylinder and the end was remade with an OPtwo flare, which held.
AS you can see most of the front braking system has been replaced with new, only the o/s caliper and flexi are original. Do you have any further ideas because at the minute drives involving regular use of brakes are out, it appears that with each touch of the brake there is residual pressure left which builds up to jam the brake, but peculiarly it appears to be only the one.
Your help or others would be much appreciated,

Cheers,
Phil

I know this isn't much help.

I know this isn't much help. But it may make you feel a little better. You are not alone. My B reg F80 had the exact same problem with the exact same calliper. It got so hot one day when I was really p'ed off with it, and drove it home nearly locked that the glass fibre mud shealed over the break disc caught fire. Managed to put it out with sea water luckely.
Any way I have changed the pads, the caliper (twice), the caliper mounting, the disks and the flexi. Stil failed the MOT becouse it was draging. I have had the car for 2 years now, and that one problem is the only one I have not been able to cure.
One thing I did find with mine to begine with was, if you drove it every day it was fine. If however you left it parked up for more than a few day's the problem was back with a vengence, then it would sudenly free off and be fine again. Now though it's there all the time. i am seriously considering changing the whole axle, just in case something is bent somewhere I can't see. Though I will master cylinder advice first, as I hadn't though of that one.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

sticking brakes

Hi, this is a long shot but I had a similar problem,and changed everything (at great expense) after my brake shields also melted on the way on holiday towing a caravan I had a word with a chap who is a race engineer to see if he had any ideas. He said check the master cyl pushrod clearance which I did and duly found it to be too tight. My master cyl had a non adjustable pushrod so needed grinding to obtain clearance, but BEWARE the rod has a cup which can fall into the servo, so gently does it or you need someone with slim fingers to retrieve it! It may be possible to adjust the clearance at the pedal, mine wouldn't but I have seen some that will.
Hope this helps...Regards Phil

brakes sticking

Hi Phil,

Did releasing the brake fluid free off the brake? If so and you've tried everything i mentioned previously then maybe its your brake pedal not allowing the master cylinder to return properly, either due to a siezing brake pedal pivot or brake light switch (if it's actuated
by the pedal) adjusted to far out and holding the pedal from its stop.

I didn't consider this before because it was only the N/S/F binding and i would expect either all the brakes or even just both fronts to be affected.

At the minute i can't think of what else could be causing your problem so i hope this helps or some one else can think of some thing obvious that i've missed,

Daz

Sticking brakes

Hi Daz,
Thanks again, I will check these points tonight. One of my friends, who is an automotive engineer dis think, when he looked at the brakes that the o/s/f was heating up slightly, but nowhere as bad as the n/s/f which was locking up, so maybe the problem does lie in the linkage. I will let you know the outcome.

Cheers Phil

STICKING BRAKES

Thanks daz, at long last the problem is solved. After all else suggested was tried the problem appeared to be solved by adjusting the brake light switch by unscrewing two turns. Have obviously now driven many miles and the brakes are operating normally without any sign of overheating or siezing on. I would never have thought of that one, seems so trivial. Thanks again Daz, nice to know there are experts to call on who know the fourtrak and its little peculiarities.

Nev K, you may wish to try this one also, you have suffered longer than I have!

Cheers, Phil.

That's just bonkers. I have

That's just bonkers. I have so got to try it.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

sticking brakes

Nev, just thought that I would let you know in case your problem still exists that fourtrak passed its MOT with flying colours, brakes in perfect balance and no further history of sticking. Obviously the positioning of the brake light switch is critical. Hope yours gets sorted with no more expense.
Cheers,
Phil

Thanks for the info. If I ev

Thanks for the info. If I ever manage to put the twins down long enough to pull my old girl out of the stingers, I'll be giving it a try.

Cheers.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

Brakes

Hi Phil, i'm glad i was able to help. Thanks for letting us know how you got on.

Sticking Brakes

Been puzzling over this one since you first posted and just had a thought. When you buy a replacement caliper you only get the sliding side of it (with the piston in), not the part which bolts onto the vehicle with the two screw in pins onto which the other part slides. If these two pins are misaligned or bent, then the sliding part of the caliper may not be free enough to move off the disc after braking. The only force that retracts the piston is the natural elasticity of the rubber piston seal, and it only moves a tiny fraction. The sliding part should move freely by hand on its pins. My apologies if this suggestion is obvious but I gather that you're desperate !!!

Actually, I have been watchin

Actually, I have been watching this thread as well, trying to nut it out. I agree with AJ. It sounded like the slide pins were jammed, but when you said the caliper was replaced, I assumed you meant the whole caliper assembly. Those pins must be straight, clean, greased, and working absolutely freely for the caliper to release properly. Are the end caps still there as well, to keep the garbage out?

Cheers
David

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