Triumphrat

12-02-2005

Hi this is my first posting and sadly it is with a problem.
I have looked through to forum and not found this problem,
My front brakes are binding when cold, after rideing for about 2 miles they free off and are fine for the rest of the day. The bike is used regularly and the problem is the same whatever time of day I first ride it, and whatever the weather, New pads were on the bike when I bought it, do not know what make they are.
I have had the callipers off and used copper slip on the slidders and back of pads, there dose not seem to be any rust or pitting on the pistons.
I could cope when the weather was wet but now it is a bit frosty am very worried about a front wheel slide.
A bit lengthy but any help gladly acepted

Many thanks to all who responded to my pleas for help,
After bleeding brakes the fault was still there so bit the bullit and went to JL and bought the seals.
A bit nervous about fitting them but was a simple job in the end, making sure that everything was meticulusly clean.
The calliper had oxydised under the scraper seals and was pushing them out. I am now a very happy Tiger rider again.

[ This message was edited by: UKTIGER955i on 2005-12-22 14:57 ]

iansoady · 12-02-2005

It would be worth getting the front wheel off the deck and removing each caliper in turn to see where the problem is. I suspect given the age of the bike that one or more pistons may be binding in the caliper. When new pads are fitted, some people just push the pistons back into the cyslinder without cleaning them, this causes a build up of ***** which prevents them sliding freely.

I'm not specifically an expert in Tiger brakes (or much else for that matter) but most calipers use the hysteresis ("springiness") of the rubber seal to slightly retract the pistons to give a running clearance. Obviously this is a fairly small force and as such doesn't take much to stop it from working.

clive955 · 12-02-2005

Agree with the above, lift the front wheel off and the deck and see which Disc is binding and slowly take the caliper apart and thoroughly clean off .

PS Green is mean

tango · 12-02-2005

I'd take both callipers off and give them a good clean with brake cleaner, use an old toothbrush or pipe cleaner, something you can get round the pistons.
While the pads are out you can give the brake lever a gentle squeeze (don't grab it) to push the pistons out slightly to make a thorough job of the pistons. The pistons can easily be pushed back in to allow the pads to be replaced.

12-07-2005

Thanks for the sugestions, I have removed the calipers and cleaned the pistons, one was a bit sh**y, also not moving very smoothly. Pumped it in and out a few times to clean it.
Onnce reassembled I thought I had cracked it but following morning same problem, just priced a piston and seal kit, S*** !! they are expensive but what price on safty.
Cheers all.

robbie · 12-07-2005

When left overnight in the rain the pads can corrode to the disc making them bind a bit in the morning until the disc is cleaned up by the braking action. You can see a pad size and shape rust spot on the disc.

This I think would be classed as normal

A more serious occurrence

When you cleaned the brakes did you remove the steel shim on the aluminium carrier?

Sometimes the area behind the shim can corrode and the aluminium furs up stiffening the brake. When used the braking load powders the corrosion and the brake frees up.

Tigerfeet · 12-07-2005

Do you know the service history of the bike?

If it still has the original brake fluid in the system then its possible that your pistons/calipers may be binding due to a metallic reaction caused by oxidation.

This oxidation can occur when water in the brake fluid is formed by condensation which then builds up over period of time, it will build up quicker if the bike is/was used throughout the winter(s).

The oxygen in the water then reacts with the aluminum parts usually at the lowest level (calipers) and this reaction then produces a white powdery substance which eventually sets like cement between the pistons and the calipers.

If this is the case the you should do something about it sooner than later as I have seen calipers seize so tight because of this process that the calipers have had to be scrapped as it was impossible to remove the pistons.

Hope you find an easy solution!

TF.

Patrick · 12-11-2005

I had got this problem myself. First kilometers I wouldn'd been able to push the bike. Riding only was possible with about 25% more thottle than normal. When the brakes heated up, everything became normal. Just until they had cooled down again.

Reason was: I used to "clean" the brake pistons with WD40. What I didn't know was: WD40 dessolves plastic and rubber.

The brake piston's shaft seals are made of rubber and they smeared all over the pistons.

The brake calippers had to be deassembled and cleaned. The pistons had to be polished. And the shaft seals had to be replaced. Now everyting is fine again.

Have fun!

Patrick

iansoady · 12-12-2005

Quote:

On 2005-12-11 14:02, Patrick wrote:
Reason was: I used to "clean" the brake pistons with WD40. What I didn't know was: WD40 dessolves plastic and rubber.

The other thing that does is degreaser (Jizer, Gunk etc) which are petrochemical based. As does petrol, cellulose thinners, etc etc......... You have to be really careful what you let near those seals.

12-22-2005

Many thanks to all who responded to my pleas for help,
After bleeding brakes the fault was still there so bit the bullit and went to JL and bought the seals.
A bit nervous about fitting them but was a simple job in the end, making sure that everything was meticulusly clean.
The calliper had oxydised under the scraper seals and was pushing them out. I am now a very happy Tiger rider again.