Back brake problem

[steveecob]

Just bought a 1981 Prolink in great condition.Love the bike but back brake sticks .A tap with a rubber mallet releases it. Any ideas of my problem before I start stripping . The pads look well worn by the way. Cheers Steve Durban S.Africa.

[steve murdoch icoa #5322]

Welcome to the site, Steve.
Sounds like a cleaning of the rear caliper is in order. Not a big job and it might not even need a rebuild kit.
After removing the pistons in the caliper i use a brass wire wheel on a Dremel to clean out the rubber seal grooves.
It could even be as simple as a dirty master cylinder. A bit of debris clogging the tiny port.
Has the bike been sitting?
What ever you do, don't ask which brake fluid to use.

[NobleHops]

Welcome to the site, Steve.
Sounds like a cleaning of the rear caliper is in order. Not a big job and it might not even need a rebuild kit.
After removing the pistons in the caliper i use a brass wire wheel on a Dremel to clean out the rubber seal grooves.
It could even be as simple as a dirty master cylinder. A bit of debris clogging the tiny port.
Has the bike been sitting?
What ever you do, don't ask which brake fluid to use.

LOLOL!

What he said, all around. Do a little searching and you will find a few threads where we go through rear (and front!) brake troubleshooting in gory detail, but for sure, if the bike has been sitting, I consider it just a good idea to take those brakes apart and give them a good refresh. Single piston calipers are pretty quick to disassemble and renew.

Do a search or two, report back with your questions and we will get you all sorted out.

[steveecob]

Thanks Steve for the advice , nice to know what to look for before starting a job. No the bike was in regular use by its previous owner even though its only done 38000 Km. I have bought new Castrol Dot 4 brake fluid, Dot 3 seems to have been taken off the market here . I hope this will be ok. I have a set of new pads from D. Silver and I think I will strip the whole system and start afresh. Will keep in touch and report any developments. Thanks again.

[steveecob]

Thanks Guys, rear brake M.S. was the problem and when stripped down I found exactly what you said 33 years of accumulated build up of crud blocking it up . New seal kit fitted after complete overhaul of housing did the trick. Decided to re-con. rear caliper , a local engineering company machined new pistons from s\s steel and a new seal kit fitted and the brake is now as good as new. Next job are the front brakes. Hope they go as well.

[NobleHops]

Thanks Guys, rear brake M.S. was the problem and when stripped down I found exactly what you said 33 years of accumulated build up of crud blocking it up . New seal kit fitted after complete overhaul of housing did the trick. Decided to re-con. rear caliper , a local engineering company machined new pistons from s\s steel and a new seal kit fitted and the brake is now as good as new. Next job are the front brakes. Hope they go as well.

In my case the rear gave me false hope about how quick it would be to do the fronts, but possibly the accounts of my own thrashings here somewhere will give you a leg up.

Great start!

[steveecob]

Thanks to Nils and Steve and the other helpful information the back brake binding problem was easily solved. front brake overhaul went just as easily. Front master cylinder was bad,needed resleeving ,new seals etc. both calipers have seals and s\s pistons fitted and bleeding was a breeze thanks to great advice from you guys . I left front brake lever taped back for 2 days and had perfect brake pressure .Now have to bed new pads in ,but bike already stops great. Total cost of both brake overhauls was around 230 dollars. Not bad value heh. Steve in Durban South Africa.

[NobleHops]

Terrific Steve!

Yeah, you're a man after my own heart with the all-new parts but this is after all your brakes we were working on, so $230 doesn't seem too bad . Very happy it all worked so well for you. What's next on your bike for us to tinker with?

[steveecob]

Just a little cosmetic work to do now, clutch seems to rattle a little at tick over ,by all accounts I shouldn't worry too much. What do the "experts" say.

[steve murdoch icoa #5322]

A little clutch noise is no big deal but a full carb synch can go a long way in eliminating the rattle.

[promethius]

Hi Guys, having a problem bleeding the rear brakes on my 1982 pro-link, the master cylinder pushes fluid through the pipe but as soon I release the plunger it sucks the fluid back. I overhauled the master cylinder and assembled as shown in the manual, calliper also overhauled as shown in the manual. There a no blockages anywhere, is there a special way of doing this or does the same method apply as for the front brakes. PLEASE HELP!!!

[NobleHops]

Hi Guys, having a problem bleeding the rear brakes on my 1982 pro-link, the master cylinder pushes fluid through the pipe but as soon I release the plunger it sucks the fluid back. I overhauled the master cylinder and assembled as shown in the manual, calliper also overhauled as shown in the manual. There a no blockages anywhere, is there a special way of doing this or does the same method apply as for the front brakes. PLEASE HELP!!!

Sounds like a technique issue to me. When bleeding brakes without a vacuum bleeder, you typically pump the brake with the bleeder screw cracked open, then quickly close the bleeder screw BEFORE releasing the lever. You will need to continually replace the fluid in the reservoir of course, but the back brake is usually very quick and easy to bleed this way.

[asacuta]

I installed stainless speed bleeders on mine: makes the job a little quicker.

[EMS]

I installed stainless speed bleeders on mine: makes the job a little quicker.

+1.!
Have been using these for some time. Really like them.

[promethius]

Thanks for all the replies, I got myself a vacuum bleeder kit. It solved my problem in ten minutes flat, what a great bit of equipment to have.