'77 GS750 brakecomplete rebuild- after market front master cylinder?

[Guest]

Bike is a 1977 GS750 with the original brake system except for steel lines. I want to rebuild or replace everything: stock single front and rear caliper, and both master cylinders. What are 70's GS owners doing these days? Rebuild kits for the calipers- are oem Suzuki parts the best way to go vs aftermarket (K&L) kits? Don't know if the pistons are good at this point, I have not disassembled the calipers yet.

I realize the rear master cylinder will have to be just rebuilt. The one I'm most concerned with is the front master cylinder- I have had corrosion issues on other 70's bikes and never gotten a good bleed/lever feel after rebuilds with oem parts. There are now a few aftermarket complete master cylinder assemblies available for Honda and Kaws that are less than rebuild kits- are they good, or junk? here's an example: http://4into1.com/replica-kawasaki-c...onda-too-14mm/

[chuck hahn]

Disassemble the calipers and masters first to see what needs replaced. If the pistons arent pitted and rusty then all youll need is the new piston seals.

Note that you need to break the bleeders loose to so youre sure they are ok and dont break trying to get them loose. Best be if they seem stuck is to heat the housing area at the bleeders and apply some penetrating oil and let them sit a while and try again.

The seals between the two halves of the rear caliper will need replaced if you break it all the way down. I suggest you do as it makes cleaning the groove the piston seal goes in a lot easier. I use a dremel and one of the brass wire brushes and run that around the groove to remove the scale and crud.

New crush washers are a good idea as well.
As for the masters. If the bores are good and the rubber cups are still supple most times all you need to do is clean the brown scum out and reassemble them. Its usually the scum build up that gets between the cups and the bores and make the masters fail to make pressure.

[chuck hahn]

List of bikes that used the common parts

FRT caliper pistons::

• 1977 SUZUKI GS400B - CALIPERS (GS400B)
• 1977 SUZUKI GS400XB - CALIPERS (GS400B)
• 1977 SUZUKI GS750B - FRONT CALIPERS (GS750B,C,N)

[hannibal]

I'm looking for a front MC for the same bike. I'm curious what you decided to go with. Also dealing with a rusty rear MC and planning to rebuild it once I get it opened up. Did you find a part number for the OEM rebuild kit? I've seen a few different part numbers.

[CrazyCloud]

I picked up a lightly used front MC from a 2008 Kawasaki Ninja 650 for my 1978 GS 750. The bore size is the same as stock, plus it has an adjustable lever. If you don't mind it not looking stock it can be a good low cost option. It does have threads for the mirror too.
Mostly you're looking for a MC with a 5/8" bore, that will fit 7/8" handlebars, there are lots of options out there.

Yes go OEM for brake stuff. If you order from Partsoutlaw and use the BANG code you get free shipping, which is a big plus for ordering OEM stuff. You will need a different banjo to fit if you go with the Kaw MC. Good luck!

[chuck hahn]

last we heard the BANG code was no longer in effect. Unless someone knows different but guess you can try it.

[CrazyCloud]

I just tried it, it took the shipping from $9.99 to $1.00. Not free, but the best shipping deal I know of for any vendor, let alone OEM.

[hannibal]

Doh! I ordered from PartsOutlaw on Friday night. Called them this morning and said they'd give me free shipping. Better late than never!