GT500 and GT front brakes

[Roger486]

Hi

Just had a look at what I have in the way of front brakes on my GT500. The caliper looks like a ceased lump of metal. It took a pipe extension on an allen wrench to shift the bolts and get it apart. The o-rings are of course destroyed and once apart it is clear that the piston is a solid lump of muck. The bleed nipple is worn round and smooth and nothing I have done so far will shift it!

From this Board I can see that the caliper is common to all of the GT bikes (?) as long as I get a right hand one! Are there other calipers that will just bolt on?

I am also chasing re-build parts fro local dealers (59100-18831 plus o-rings and dust covers), but what is available in the Northern Hemisphere?

I do have a master cylinder kit 59600-45821, so hopefully I am OK at that end.

[Coyote]

You are going to need caliper kit # 59100-18834. Kit contains a new piston and seal. I think the axle o-rings are in there as well. Dust cover and bleed screw sold separately. You might want to go with an aftermarket speed bleeder. It has a built in check valve and makes brake bleeding a breeze by yourself.
You have to replace the bleed screw anyway. Try clamping the bleed screw in a vise. Then heat the surrounding aluminum with a propane torch. Then try to break it loose by turning the caliper body. You are not blessed with space and probably will get 1/8 turn at best, but once it breaks loose it should come right out.
Alternately, look for a good used caliper from a 380 or 550. They are on ebay all the time.

[oldjapanesebikes]

There were a couple of different suppliers used for these - ASCO and Tokico. The Tokico callipers and master cylinders were common across most of the GT line, but the GT500 for 1977 at least was ASCO and the calliper piston is no longer available. I've used a Tokico piston as it is the same bore and fits OK, but the seals and dust boots are all different, as is the master cylinder rebuild kit.

Any idea which one you have ?

[Roger486]

No, I am afraid that I don't... however I have picked up a complete brake system off eBay that 'looks' OK and I have ordered a caliper rebuild kit from Japan. I have a master cylinder kit... lets see if I have the right bits from amongst that!?

[Roger486]

GT500 calliper A.jpg

Well I now have two master cylinders and two calipers, both identical Tokico. My original ones were very corroded. The new eBay ones less so... at least they still had fluid in them which is a start. I have also managed to source both a master cylinder and a caliper recon kit from Suzuki Japan (the caliper kit being painfully expensive!)

I got the 'new' caliper apart, and have run into much the same problem that I had with the original. How do you remove the old piston from the caliper. There is corrosion and it is well and truly stuck!

I am yet to break out a propane torch to heat the surrounding aluminum... any other suggestions or advice?

GT500 calliper components A.jpg

[Coyote]

Tap the piston in slightly to un-stick it. Replace and tighten the bleed screw. Then use compressed air in the inlet hole. This is messy so wrap a rag around it. Requires about 100 psi. It will just 'pop' out.

[Roger486]

Tap the piston in slightly to un-stick it. Replace and tighten the bleed screw. Then use compressed air in the inlet hole. This is messy so wrap a rag around it. Requires about 100 psi. It will just 'pop' out.

I don't have a propane torch ... or easy access to compressed air (except in a scuba cylinder)... so as I was going to the beach to my parents, I took it with me. My father did not have a torch either, so we took it down the road to a retired engineer who has a good workshop.

He did not like the sound of either technique (heat or compressed air) and he had a third option. He blocked off the holes. Put a grease nipple into the bleed hole and used a grease gun. A few pumps and t gently popped ou with no mess; just wipe the grease out of the caliper.

Now I just have to tackle the infamous cir-clip in the master cylinder!

[Roger486]

I have a master cylinder kit 59600-45821 which looks exactly like the one in the picture below labeled 9600-4582 (off eBay that retro-motorcycles claims fits the GT500). The version of the parts catalogue that I have gives a parts number of 59600-18824, they all look the same, and the on-line parts catalogues say that 59600-45821 supersedes: 59600-18824 and 59600-45820.

However that same on-line catalogue has two pages for the GT500A master cylinder and although the diagrams are exactly the same, the key lists different parts numbers. For the master cylinder it lists 59600-33810.

So I am confused! can anyone shed any light... and does anyone have an exploded diagram that shows how the kit goes together?

Master kit.jpg

[Roger486]

Well it looks like I may have answered my own question. It seems that I may well have both a ASCO and a Tokico master cylinder and two Tokico calipers.

IMG_0844.jpg

IMG_0845.jpg

So hopefully I am set, as I think that I have both recon kits for Tokico (caliper and master cylinder)

[oldjapanesebikes]

Correct - that's why I was asking if you knew which one you had - the internals are similar, but not the same. The ACSO master kit is 59600-33810. The key difference being that shaft that the lever actuates (and is covered by the dust boot) is a smaller diameter than is used on the Tokico.

For assembly, the parts diagram is as good as anything else you are likely to find.

[Roger486]

I admitted defeat on extracting the cir-clip and went into my Suzuki dealer... and they did it for me in a flash. I took the opportunity to see the order things came out The parts diagram unfortunately only shows the piston, not the position/order of the spring or seals.

But I have it now. I may post a picture to show others?

[drøn]

Hope it's okay to hijack this thread as to not start a new one on the (almost) same subject.
I tried to bleed my front brake, Tokico, yesterday, but destroyed the bleed nipple in the proces. I need a new one, what to look for?
I also saw that one of the pads was almost worn out. are these proper replacement? http://www.ebay.co.uk/itm/290474683056? ... 1423.l2649" onclick="window.open(this.href);return false;

[Roger486]

Hope it's okay to hijack this thread as to not start a new one on the (almost) same subject.
I tried to bleed my front brake, Tokico, yesterday, but destroyed the bleed nipple in the proces. I need a new one, what to look for?

These guys advertise and sell on eBay, but I purchased direct... http://www.speedbleeder.com/" onclick="window.open(this.href);return false;

As for the pads, I believe that the 500 takes the same pads as the 550 and the 750...

[drøn]

thanks, but what bleeder size should I go for? Couldn't find it on their chart...

[Roger486]

thanks, but what bleeder size should I go for? Couldn't find it on their chart...

I got SB7100SS off their site.