No Rear Brake Pressure -- "Kit" rebuild a good idea?

[davedoom]

Hi all,

My 83 650L was knocked over when parked -- then the rear brake light wouldn't come on so I (idiotically?) pumped the brakes and, I think, ruptured the rear brake master cylinder (but the brake light works again...).

There's now Zero rear brake pressure, I bled the brakes, took it to a mechanic as well who suggested I needed a new rear master cylinder.

I'm considering getting a kit:
http://www.bikebandit.com/k-l-master-cylinder-rebuild-kit?mg=3638&t=1&td=1

Does anyone have experience with these kits?

Is this something you'd recommend?

Other thoughts/suggestions?

Thanks!!

Dave

 

[salty_monk]

Better to buy OEM replacement seals/Pistons than KL is the common experience here.

You can still get them from Bikebandit. Check the piston bore isn't pitted to, if so look around for a good 2nd hand piece.

 

[davedoom]

Awesome. Thanks for the advice.

They have the assembly for $170 (vs. $30 for the rebuild).

I'd love to hear from anyone who has either done the rebuild, or who has replaced the complete assembly -- basically looking for information on:
1) What kinds of issues were run into on the rebuild and

2) How challenging/straightforward it might be to replace the complete assembly.

Thanks!!!

 

[Nessism]

Do as Salty Dan suggests and tear down the system. Removing the master cylinder piston is easy, and after cleaning it out you can inspect the inside with a flash light to see if there is any pitting. Same goes for the rear caliper; You can get new seals for the rear caliper if the pistons are not pitted, or get a piston kit that includes the seals if they are. While the system is torn down get yourself a teflon/stainless brake line. The only way to know what needs to be done is to tear down the system first.

 

[DPage]

Don't spend $170 on a new one, chances are your old one is rebuildable. I've rebuilt three rear masters on my bike and others using OEM rebuild kits (about $25) and all of them work like new.

 

[Nessism]

Don't spend $170 on a new one, chances are your old one is rebuildable. I've rebuilt three rear masters on my bike and others using OEM rebuild kits (about $25) and all of them work like new.

Chances are reasonable that you can simply install a master cylinder kit but you need to check the master bore carefully for pitting first. I've seen a goodly number of corroded masters from the inside out.