'79 GS850 what did I get myself into?

[canuckxxx]

I'm waiting for rings and a head gasket so I have turned my attention to the rear brakes.

When I bought the bike we had to pry the rear caliper off the disc in order to load it into my truck. So I have to whole rear brake assembly on the workbench and am taking it apart starting with the master cylinder. I have the cerclip out but the piston is too gummed up to come out. Any ideas?

i think if I can get the MC working I can use it to force out the caliper pistons. Surprisingly the caliper piston don't seem to be stuck too bad.

[canuckxxx]

I'm waiting for rings and a head gasket so I have turned my attention to the rear brakes.

When I bought the bike we had to pry the rear caliper off the disc in order to load it into my truck. So I have to whole rear brake assembly on the workbench and am taking it apart starting with the master cylinder. I have the cerclip out but the piston is too gummed up to come out. Any ideas?

i think if I can get the MC working I can use it to force out the caliper pistons. Surprisingly the caliper piston don't seem to be stuck too bad.

OK times up. The answer is that you find a drill bit that is just the right size to fit the hole in the other end ( where the banjo bolt goes), put the non-drill end into the hole and push it against the work bench with the MC body. The piston came out very easy.

So I cleaned up the MC and put it back together, connected the hose and calliper. Opened up the bleeder and sucked it full of brake fluid with the vacuum pump. When I pumped one of the calliper pistons moved out so I put a c-clamp on it and moved the other out a bit. Put a piece of 1/4" plate between the piston (where the disc would go) and worked the brake lever...brake...release...brake...release etc etc. All seems to work OK now.

[Nessism]

Hope you are going to open that caliper and clean it out. There is likely sludgy brake fluid chunks inside. And replace all the brake lines because they are 40 year old rubber parts that have been exposed to the elements.

[Sam 78 GS750]

Hope you are going to open that caliper and clean it out. There is likely sludgy brake fluid chunks inside. And replace all the brake lines because they are 40 year old rubber parts that have been exposed to the elements.

^^^^this right here... easy enough job, and more than likely needed.

[canuckxxx]

Yes, I will eventually rebuild things depending on how it runs and drives and handles and if I find some big problem. This bike is an unknown quantity for me so I'm going slow. My main goal right now is making it functional so I can see what I have but spending minimal money.

Brian

[canuckxxx]

I'm working my way through the frame and right now I am looking at the steering stem. This picture is what I found. The only lock nut is the choke thing whereas the parts fiche shows a separate nut. Is my setup possibly correct or am I going to have to buy that nut?
closup of stem.jpg

[Big T]

Yes, I will eventually rebuild things depending on how it runs and drives and handles and if I find some big problem. This bike is an unknown quantity for me so I'm going slow. My main goal right now is making it functional so I can see what I have but spending minimal money.

Brian

Safety should be your primary issue. Having a brake seize up on you at speed because you didn't take 15 minutes to pull the piston and see what is inside is definition of "unknown quantity"

[canuckxxx]

Safety should be your primary issue. Having a brake seize up on you at speed because you didn't take 15 minutes to pull the piston and see what is inside is definition of "unknown quantity"

Point taken Big T. "Brakes seizing up" reminds me of an experience I had with another GS850 I had about 10 years ago. As I was riding the rear brake gradually started to drag and then finally stopped the bike. I parked the bike and got a ride home. When I came back a couple of hours later the brakes were free and I rode home. If I remember correctly the thought on GSResources was the some tiny drain hole in the MC had plugged up which prevented the calliper to release.

Does this ring any bells? Seems it is a well known issue with these bikes.

[canuckxxx]

Safety should be your primary issue. Having a brake seize up on you at speed because you didn't take 15 minutes to pull the piston and see what is inside is definition of "unknown quantity"

Point taken Big T. "Brakes seizing up" reminds me of an experience I had with another GS850 I had about 10 years ago. As I was riding the rear brake gradually started to drag and then finally stopped the bike. I parked the bike and got a ride home. When I came back a couple of hours later the brakes were free and I rode home. If I remember correctly the thought on GSResources was the some tiny drain hole in the MC had plugged up which prevented the calliper to release.

Does this ring any bells? Seems it is a well known issue with these bikes.

[canuckxxx]

Made some progress on my GS.

Concentrating on the frame now. Cleaned and repacked the swing arm and steering head bearings. Spent the last two days cleaning the frame for painting using SPRAY 9 cleaner, Scotchbrite pad and scrub brush. Today I sprayed Rustoleum Painters Choice semi-gloss.
image.jpg

[canuckxxx]

SPRAY NINE is a cleaner that was recommended by a neighbor who worked on a fracking crews where they use a lot of it. It removes grease, oil, and wax so you have a squeaky clean surface to paint on.
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[canuckxxx]

Still need to paint the centre stand, kick stand and battery box. Then clean up the wiring harness and put it and the battery box back into the frame. Etc, etc, etc.

[canuckxxx]

Are there rubber grommets that go into the three mounting holes for the rear cowl?
image.jpg

[canuckxxx]

The front wheel that came on my bike has as a bent rim so l've bought a replacement. I have the damage wheel off; should the axel slide out of the wheel? Mine doesn't.

Advise, ideas will be appreciated.
image.jpg

[Nessism]

The front wheel that came on my bike has as a bent rim so l've bought a replacement. I have the damage wheel off; should the axel slide out of the wheel? Mine doesn't.

Yes, the axle should slide out. Try hammer. If it doesn't come out easily it's probably damaged.