I'm having problems with the rear brake on the Saturno 500 IOM.
I have bled it a few times, but it won't bleed properly.
Pressure can be gained by a few small pumps on the lever and it is fine, but if left for 2 weeks it needs pumping again to get pressure. Yesterday the piston jammed fully in. That was easily fixed by pushing out from the banjo end and bleeding again. Now it is fine but I am thinking the rear master cylinder needs a rebuild?
There are no markings on the rear master cylinder. Does anyone have a link to a rebuild kit, or let me know the make of master cylinder if I need to replace?
Thanks,
Rangy
Saturno rear brake master cylinder rebuild kit
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Re: Saturno rear brake master cylinder rebuild kit
sometimes those brake pumps tend to wear out. Due to some water causing rust.
So bying a repair set may last some time, or not
New pumps are rather hard to find.
50mm bolts distance, 11mm piston
Maybe this one is still available
Usually it isn't
https://www.stein-dinse.biz/product_inf ... _id=216253
Also some Nissin pumps are adaptable.
you may search here for:
Saturno Bremspumpe and use some kind of translation tool. Deepl?
ciao Joachim
So bying a repair set may last some time, or not

New pumps are rather hard to find.
50mm bolts distance, 11mm piston
Maybe this one is still available
Usually it isn't

https://www.stein-dinse.biz/product_inf ... _id=216253
Also some Nissin pumps are adaptable.
you may search here for:
Saturno Bremspumpe and use some kind of translation tool. Deepl?
ciao Joachim
Re: Saturno rear brake master cylinder rebuild kit
Thanks Joachim, I was able to order the replacement cylinder so hopefully that will work out.
Re: Saturno rear brake master cylinder rebuild kit
Finally got the new cylinder.
Then the hydraulic switch needed replacing as the original was too long.
The incorrect switch was sent, but Stein Dinse quickly sent the correct one.
The cylinder is not exactly the same, so still needs some adjustment.
Good enough for a nice ride in the warming weather in Tasmania



Then the hydraulic switch needed replacing as the original was too long.
The incorrect switch was sent, but Stein Dinse quickly sent the correct one.
The cylinder is not exactly the same, so still needs some adjustment.
Good enough for a nice ride in the warming weather in Tasmania




Re: Saturno rear brake master cylinder rebuild kit
I did learn something which is apparently common on a few other motorbikes as well.
Where brake calipers are lying horizontally similar the Saturno,and if you get alot of air into the system (like replacing cylinder etc) air will get trapped in the calipers which will not be removed through normal bleeding using the brake lever. You need to either use a vacum pump, or remove the caliper so that the bleeding nipple is pointing vertically up (while bleeding with the lever) to get the air out.
The brake works perfectly now.
Ready for the Oatlands Bike Show on the weekend:

Where brake calipers are lying horizontally similar the Saturno,and if you get alot of air into the system (like replacing cylinder etc) air will get trapped in the calipers which will not be removed through normal bleeding using the brake lever. You need to either use a vacum pump, or remove the caliper so that the bleeding nipple is pointing vertically up (while bleeding with the lever) to get the air out.
The brake works perfectly now.
Ready for the Oatlands Bike Show on the weekend:
