I need another rear master cyl body:corrosion.

[grcamna2]

I want to replace just the rear master cylinder 'body' on my 83' GS750ES because of water corrosion.Do you know of any other models which use the exact same part,possibly the 550ES or 1150 ?

[phydeauxmutt]

That part number cross-references to the '83 750 and the '85 700.

[grcamna2]

Yes,that part #69600-31300 is for the complete rear master cylinder assembly:inclusive with every part needed.I want to know if anyone has researched which master cylinder main 'body' has the same exact specs(on another Suzuki model of similar year,14mm inner piston,etc.)to be a direct swap with mine,then I could use the same parts from my old one like the lower boot,piston rebuild kit/cups.The online parts specs don't give a separate part number for that part:there is no part number for it. thanks,Bill

[Maddevill]

I was searching something similar and someone posted about using a Ninja 300 master with minor modifications.

Mad

[Nessism]

Salty_Monk installed a newer rear master on his 1000E and posted photos as a guide. Can't remember exactly what he did but it was a fairly simple mod.

[grcamna2]

I was searching something similar and someone posted about using a Ninja 300 master with minor modifications.

Mad

I remember reading your thread and posting to it with this question;did you find the inner bore to be in good enough condition to rebuild it? Was there any corrosion ?

[Maddevill]

Even though my master cylinder piston was basically stuck in the bore for 3 days while I soaked it, the bore itself
looked excellent when I finally got it out. Bike had sat unused for at least 6 years. I rebuilt it and I expect it to work.
Mad

[grcamna2]

Even though my master cylinder piston was basically stuck in the bore for 3 days while I soaked it, the bore itself
looked excellent when I finally got it out. Bike had sat unused for at least 6 years. I rebuilt it and I expect it to work.
Mad

What fluid did you soak it in? I used Liquid Wrench on mine and it took about 4 days:that piston was really jambed-up.

[Maddevill]

Same thing. WD40 then liquid wrench. On advice from here I heated the housing with a small torch and tapped the body
with a small brass hammer. After about 5 minutes the piston popped out. I expected it to be junk but the only part that was
stuck was the very top I guess.

Mad

[grcamna2]

Same thing. WD40 then liquid wrench. On advice from here I heated the housing with a small torch and tapped the body
with a small brass hammer. After about 5 minutes the piston popped out. I expected it to be junk but the only part that was
stuck was the very top I guess.

Mad

You heated the outer body with a torch? I will consider that also

[Cipher]

I was trying to x ref this but got tired. The bike specific parts number for the whole assembly is of little help but I do recall seeing the core (unpurchaseable bit ) on at least one other model bike and there certainly could be more. All the plumbing and rods amd such were different but the core the same.

[grcamna2]

I was trying to x ref this but got tired. The bike specific parts number for the whole assembly is of little help but I do recall seeing the core (unpurchaseable bit ) on at least one other model bike and there certainly could be more. All the plumbing and rods amd such were different but the core the same.

I get very tired doing that also;thank you for having a look.
The outlet on my orig. 83' 750ES rear master cylinder comes out 'elbow shaped' straight back;some others from the 550ES and 1150 have the outlet facing toward the swingarm and others toward the top.The body on mine also has the reservoir inlet elbow with 2 small screws holding it in and it is outboard close to where my right foot is.The other ones I notice that the reservoir inlet is all the way on the back side of it:that's the place where my bike has the rear brake stop switch spring so those other ones won't fit.I'm still trying to compare with different pics to see if I can find a 14mm size piston rear master cyl. to match-up.

[Maddevill]

Yes. Mainly around the part the piston was stuck in.

Mad