Locked up brakes

I just got a 79 MK2 today all hell broke loose. While sowly test driving I noticed there was not a lot of give of squeese room on the front brake. I was gently putting some pressure on the lever. VERY gently. It should have made no differance or stopped anything. Then the front wheel locked. Now there is no play in the front master cylinder and the lever is like a rock.

I have not looked at anything or tore anything apart but this is a bike riders worst nightmare.
It has the duel front brakes and everything is spotless no fluid anywhere. It is like a check valve is stuck somewhere but I don't think the brakes have one. I think the master cylinder self destructed inside. I have a manual but am to shaken up to look at anything yet.
Has anyone else had something like this happen?
Ron in arkansas:blush:

Post edited by: rgpbeme, at: 2006/06/14 01:01

Scary!!

Here are my thoughts:

All the dual disc front brake systems on the KZs are very similar. It is a simple system, made up of the Master cylinder, the brake lines, and the two calipers (with the pads to squeeze the discs). There is not a lot to go wrong in the way you experienced, other than poor maintenance of the system. My guess is that the fluid in the system has not been purged and replaced in a long time, and so you have gelled brake fluid, plus moisture in the system causing rust/crud that has jammed your calipers. This is not uncommon in bikes that have been sitting outside for a while, but the extent of your symptoms is rather extreme.

If I were you I would do a complete disassembly of the brake system components (calipers and master cylinder), and if there is any sign of corrosion at all I would at least rebuild each item, and maybe even replace the pistons and calipers if if looks like that is needed. Disassemble, clean, replace parts as needed, lightly hone the cylinders, reinstall parts, bleed system, and test result.

Note that Z-1 Enterprises likely has rebuild kits for your system components.

Also, I would do the same on the rear brake system too. Chances are it has been as poorly maintained as the front.

If you do not feel competent to do this, find a good independent shop to do it for you. Your life depends upon your brakes.

You are very lucky you did not have a serious accident. This should be a lesson to those of us who pick up a new bike to check out all the systems before going for much of a ride. Also, I would question the prior owner about his maintenance of the brake system. Did he represent that it was ready to ride? If so, I would press him to contribute to the fix.

just went thru the same type of problem, rear on a ltd1000.
the problem was the master cyl, one of the cups tore and hung the piston,
z1 should have the parts, kind of expensive for what you get though