Front Brake Caliper Help!!

Ok, so I'm kind of new to working on motorcycles, but I just bought an old 1975 KZ400D and I want to try to do as much of the work myself on this bike as I can. That being said, here's my question:

By front brakes aren't reacting at all when I pull the brake lever. The brake lever pretty much just pulls all the way to the handle bar with little to no resistance. So, I've been doing some research and from what I've read, I think I need to bleed out the old brake fluid becasue when I look in the master cylindar, it looks yellow. Well, as I’m reading how to do this in my owners manual, it says to attach a hose to the bleed valve and then turn the bleed valve counter clockwise to open it up. There’s one problem with this, the bleed valve on my bike has been completely rusted off and there is still half of it stuck in the caliper. There’s only like a millimeter of the screw showing out of the top, so I can’t really get a hold of it to screw it out.

Any advice? Am I going to have to buy a new caliper?

I found one caliper online that is exactly what I need, but it's $200!! That seems a bit steep to me. I also found one on Ebay for $25, but it's for a 1975 KZ400S and I have a 1975 KZ400D. Does anyone know if these 2 different models have compatable calipers? Also, if I could somehow get the bleed screw out of my caliper, could I put a different bleed screw in mine from a different year/model of KZ?

Thanks for the help!! I really appreciate it!! I have to get my bike ready to pass inspection by next Tuesday, or I have to pay a late fee!!

i think you could drill it out and then try to get it with an "ez out" if that doesn't work you'll need a new caliper.

these are the bikes that your caliper will fit.





KZ400 (1974)
KZ400-A1 (1977)
KZ400-A2 (1978)
KZ400-D (1975)
KZ400-D3 (1976)
KZ400-D4 (1977)

If you can get it out with an EZ Out, you should be able to get a bleed screw at your local auto supply store. Bleed screws are pretty standard.

Thanks for the help! This may be a dumb question, but what is an "EZ out?"

That is good advice, I didn't realize that bleed valves were that common, or that they were universal for that matter. (as I said, I'm new to this) :silly:

It's a screw made specifically to extract other threaded screws, bolts, etc. that have sheared the head. Go you an auto supply store and tell them what you're doing and they'll be able to get you one to fit.

Thanks, I'll do that. I've been looking up bleed valves on the internet and I came across a "speed bleeder." Does anyone have any experience with these? Would you reccomend them? They're only $7 and it says it allows brake fluid and air out, while not allowing any air in, allowing you to bleed your brakes on your own.

Also, does anyone know what size bleed valve I would need for a 75 KZ400D?

Thanks again for all the help!!!

When using the ez-out, especially on a small broken-off screw, it's sinfully easy to break off the small drill bit being used to first drill a hole into the center of the small screw (an iffy proposition to begin with) and be then left with a broken drill bit stuck inside the broken screw. Which then presents an even more difficult proposition than square one.

Let's say an extra careful drilling job was successfully performed without breaking off the drill bit. Then comes the small ez-out. And guess what. It is also sinfully easy to break off the ez-out and be left with a broken piece of ez-out jammed ever so tightly inside the broken screw. Another even more difficult proposition than square one.

If feasible, just before applying counter-clockwise torque to the ez-out, would heat the surrounding area in hopes of expanding it somewhat so as to help loosen its grip on the frozen screw.

Believing I may hold the record for breaking off ez-outs, but if not, must surely be in the top ten. :ohmy:

Good Luck!

Addendum -- if feasible, file smooth the top of broken stud and use a center punch before drilling.

I love the speedbleeders, they make life a lot simpler. Got them on my '82 kz750 and '79 kz400. I'm pretty sure that the older Kaws all use the same bleeder, SB7100S.

Good luck!

Thanks for the input, and the size info! I think I'll get the speed bleeder. Now I wish I didn't just spend $40 on a brake bleeder vac kit a couple of days ago!! Oh well.

upon reding your first post, the whole brake system needs to be rebuilt, master cyl and caliper. along with a good flushing of the system.
you will need to also disasemble the caliper to drill out the broken bleeder valve, and if you are not succesful in removing it you can buy one that has a larger thread size, you will need to buy a tap for it,but cheaper than a new caliper.
Any time I rebuild the brakes I am now using the dot5 fluid,,dosent mess up the paint, has a higher temp rating, dosent attract water,, my 2 cents

I'll concur on BSKZ650's post about needing to rebuild entire brake system. As for the broken off bleed screw. I'd suggest taking it to a local machine shop and see what they would charge to extract it. In my past, on several occassions, it has been worth the $20 bucks or so I was charged to have someone else extract a broken stud or screw. It's just an option. But, espscially if you have minimal machining experience, turning that problem over to a more experienced expert was well worth it for me. However, if you chose to try this yourself, I do recommend taking the caliper off the bike. bleeding out the brake flud, as best possible, and then using a butane torch to heat up the screw when trying to remoce it. Heat will often loosen up the gunk that freezes threads up and makes removal easier. Of course afterward, the caliper will need to be rebuilt. But, it needs it now anyway. Just a thought.

Terry!

Yeah, I was afraid of that. I found a master cylinder rebuild kit on Ebay for about $25. Does anyone know where I can get a front caliper rebuild kit? I couldn't find one of those anywhere.

Also, I still can't get the nut loose from the brake valve and I'm starting to strip it. Any advice?

Thanks!!