Front brake master for 1987 GS450L??

[Daseincycle]

Can someone recommend a source for the front brake master cylinder on a 1987 GS450L? My local dealer says that this part has been discontinued. I've bought several "substitutes" on eBay but they do not provide adequate braking performance (I can squeeze them to the handle bar and not come close to locking the front wheel...and believe me, they have been properly bled and adjusted).

Any input would be greatly appreciated, as I cannot ride until I have a new and reliable master.

[Dave8338]

Welcome to the GSR.

I use several sources for parts, it just depends on what I need.

http://www.bikebandit.com/suzuki-motorcycle-parts/oem-parts

and Cliff, a member, has a great info site of his own http://members.dslextreme.com/users/bikecliff/

By the way Cliff will be along shortly to throw down the red carpet.
Until then, feel free to use the search feature and again, welcome.

Dave

[doctorgonzo]

First, never go the dealer for anything other than an oil filter.

Bike Bandit lists the part as available, $176.00 for the whole assembly, but I bet it's not the problem, as any functioning one from a similar bike should work.

[DanTheMan]

If you can pull it to the handlebar, there is either still some air in the system, you've got a leak or you need new brake line hoses. Lot's of threads on here about bleeding the front brake, and they do work.

[Nessism]

Regarding not being able to lock the front brakes, if you still have the stock rubber brake lines installed, get those old decrepit things off the bike ASAP and install either some new stock lines or better yet, some Teflon/stainless lines. The firmer lever feel afforded by Teflon/stainless lines will allow you to put more pressure on the brake pads, which will increase stopping power. Also, it might be a good idea to get some new brake pads, particularly if the old ones are oil/brake fluid soaked. Regarding the master cylinder, you can get a brand new master cylinder off ebay for about $75 that has a 14mm piston, which is the right size for a single disc front brake. Personally, I think you’d be better off rebuilding a stock Suzuki master cylinder assuming the metal in the bore of the master is not pitted from corrosion.

[doctorgonzo]

Ed is correct on SS brake lines. I now CANNOT take my lever all the way to the bar, it stops about an inch short and it would take Conan to pull it any further (and the you'd be doing a stoppie at that point anyhow).

[salty_monk]

14mm is standard for all single disk bikes I've seen so far... 5/8" is standard for all dual disk bikes but this wouldn't have the affect you're seeing if you got one of those... it would have the opposite affect.

Make sure the brake bleeders aren't letting air back into the system. I would bet Air first, lines 2nd with bad pads also being an option.

Does it "pump up" (i.e. get firmer if you pull it several times in quick succession - if so it's definitely air).

Dan

[Daseincycle]

Hi all-

First, many thanks for the warm welcome. I've been amazed by how welcoming the motorcycle community is, and I'm happy to be a part of it. I had to fight for almost a year to get a NJ title for my GS, jump through hoops to get my NJ license endorsed, and i finally get to dig into my bike and fix it up. It's all been 100% worth it, and I couldn't be happier to have the bike.

Now, the reason that I suspected the replacement MCs were not the right size is because my original master wouldn't squeeze to the handle, and stopped on a dime. The two replacements that i've tried went right to the handle, and braking distance was uncomfortably long. Stupidly, I tried to take up some slack by overtightening the adjustment screw to "pre-load" the master cylinder. It seemed fine at first, but a few miles later I looked down to see my front caliper nearly locked and shedding sparks. Needless to say I will need to replace front pads and probably the rotor at this point. I'll also pick up a braided steel line while I'm at it.

I'm familiar with bleeding automotive brake systems, and successfully bled the original MC using the same technique that I used on the replacements (turn fork to right lock, squeeze lever, open screw, close screw before fluid stops flowing, release lever, repeat). I flushed through about a pint of fluid this way before giving up.

So why replace the original MC? There was significant rust in the reservoir when i bought the bike, the lid leaked fluid, and the sight glass was no longer opaque. i didnt want to get caught off guard drawing air into the lines because of low fluid.

Thanks for the parts links. I don;t like the idea of dropping $180 on a new MC, but better that than unreliable brakes. Does anyone know of a rebuild kit that includes the sight glass?