13 replies to this topic

[Craig]

Had a problem as you might already know with my brakes for a a few days now...
All seems fine,and then the brake lever will go hard and it feels like the brakes are binding,a few pumps later and it goes away,brakes perfect for a while,then exactly the same.....
I have tried cleaning the callipers and pistons and greased them with copper grease,the pistons are now moving freely,resetting the Pistons,cleaning the "brake bobbins and giving the system a thorough bleeding through.....
This morning,which is not usually the norm,when first moving my bike,the front wheel was completely free (it usually sticks a little,and a few pumps and it's free,so all looked promising !!!...
About 5 mile up the road when I thought all was too good to be true,it was and the brake lever went hard and it felt like the brakes were binding again ??....
I know this TDM is supposed to be a "love,hate" relationship.....
But this problem has been all hate at the moment.....
Thought the brake fluid would be pretty much new now after I did a good bleed through,so apart from that any others ideas please ??...

[TYREDNGRUMPEE]

What pads are you using?

Next time this happens put the palm of your hand on both calipers.

Chances are that they are warm/hot.

Sintered pads generate heat to the caliper and cause the fluid to expand.

Check that heat shields are fitted to the rear of the pads.

Make sure your reservoir is not over filled ( air bubble in window) and that the breather slot on the reservoir lid to the air gap above the rubber bellows is free and breathing.

Edited by TYREDNGRUMPEE, 26 May 2015 - 05:54 pm.

[Dougie69]

Hi Craig try back bleeding the brakes use the Pistons to force air up to the reservoir check that all the banjos are tight and copper O rings are all ok maybe a reservoir rebuild kit also what lines are on if originals they may need to be replaced depending on the age of your bike patience patience pationce oh also try to tie the brake lever on overnight and see if you get any fluid coming from anywhere just a few things I have had to do in the past hope you get it sorted

[steve27bha]

....

I have tried cleaning the callipers and pistons and greased them with copper grease,the pistons are now moving freely

.....

They will not continue being free.

Go back and strip out the copper grease. Any grease other than red rubber grease or a silicon type made for it will make rubber expand. This will make your piston seals jam the pistons in the out position, causing brake drag etc..

I can only assume there is some freedom left to allow the brakes to free off occasionally, but you need to do this ASAP for safety.

I suggest you strip out the greased seals, clean thoroughly and replace with new. Follow the service manual for reassembly and use brake fluid as lubricant to reassemble the pistons into the calipers. If you feel the need to seal the gap between piston and caliper body use red rubber grease.

If you PM & ask nicely I can send you a small tub of RRG.

Edited by steve27bha, 26 May 2015 - 09:32 pm.

[celticbiker]

Do you have the original Robert houses on it?

[JBX]

They will not continue being free.

Go back and strip out the copper grease. Any grease other than red rubber grease or a silicon type made for it will make rubber expand. This will make your piston seals jam the pistons in the out position, causing brake drag etc..

I can only assume there is some freedom left to allow the brakes to free off occasionally, but you need to do this ASAP for safety.

I suggest you strip out the greased seals, clean thoroughly and replace with new. Follow the service manual for reassembly and use brake fluid as lubricant to reassemble the pistons into the calipers. If you feel the need to seal the gap between piston and caliper body use red rubber grease.

If you PM & ask nicely I can send you a small tub of RRG.

 

100% agree.

 

Brake piston seals are made of ethylene-propylen rubber as it has good resistance to glycol-based brake fluid, heat, cold, ozone, but poor resistance to oil, grease & fuel.

Imho RRG may be applied to prevent salt corrosion, in case you ride a lot during winter.

[Craig]

Thanks for the replies......
I am using sintered pads,and yes when this happens they do feel very warm indeed,they do have the heat pads fitted as well,the reservoir does have an air bubble,but I haven't checked the breather slot .......

Yes it looks like the bike possibly does have the original hoses on it (?),I have not tried "back bleeding" the system but all hoses and seals appear to be ok & leek free as I did the "cable tying" break lever trick overnight and bleed again without success .....

So it really does look like the callipers again this time,perhaps I should of heeded earlier advice and replaced the complete callipers with a good used set (lesson learnt),so that's the route I will do now,kind of thinks it makes sense as although,and I quote "patience,patience,patience" my relationship with this particular set has run its course,as IMHO when I first inspected them they were not at there best.......

[TYREDNGRUMPEE]

If you have placed grease directly to the rubber seals then this is deffo what your issue will be.

I've had rubber expand and I've had to use a hammer and drift to separate car calipers before that have rubbers contaminated.

Rubber between metals is a pain to break.

If so and you choose to use the original calipers, you should pump out all the pistons 85% before popping the first piston. Messy and easier typed than done.

[TYREDNGRUMPEE]

If you have placed grease directly to the rubber seals then this is deffo what your issue will be.

I've had rubber expand and I've had to use a hammer and drift to separate car calipers before that have rubbers contaminated.

Rubber between metals is a pain to break.

If so and you choose to use the original calipers, you should pump out all the pistons 85% before popping the first piston. Messy and easier typed than done.

 

I've got a set of complete originals here in Swindon. RolfieB gave them to me. Pass it forward.

They may need servicing themselves but you can have them if you can collect them.

A bit too heavy to post.

Comes with hoses.

May have the master cylinder and brake lever for myself, just in case.

[celticbiker]

As it appears you have the original houses on, I wouldn't be in the least bit surprised if it's started breaking down inside and there is a loser piece of rubber behaving like a valve or flap and causing the intermittent problems you are having

[Craig]

I've got a set of complete originals here in Swindon. RolfieB gave them to me. Pass it forward.
They may need servicing themselves but you can have them if you can collect them.
A bit too heavy to post.
Comes with hoses.
May have the master cylinder and brake lever for myself, just in case.

Many thanks for your kind offer TYREDNGRUMPEE . I will take you up on it please,Swindons not a million miles away,and who knows I might experience the wonders of The magic roundabout?.....
It makes sense as I can store the bike in the garage whilst servicing this set. I've sent you pm
Thanks again and to all the other replies for which I'm very grateful indeed :-) .....

[dapleb]

Normally atwix Swindonia and Devonia frequently but will be at least a few weeks till my next jaunt but depending on where in Devonia ewe are oi moight be able to elp. Lettuce snow if any use.

[TYREDNGRUMPEE]

So, all is good.

Good job.

 

There's an ebay seller,(Powerhouse) based in Sheffield, that sells complete full seal/washer/nipple/grease caliper kits for most motorcycles, at about half the going rate.

 

 

http://www.ebay.co.u...r/powerhouse-uk

[Craig]

Yep at the moment it's "Work in progress" !!...
Just waiting on the last few bits & bobs,taking my time,doing it right & taking no chances,guess we're talking brakes after all :-)