When to rebuild the master cylinders?

[Jcol]

I see from various parts venders quite a few master cylinder rebuild kits so I assume that there has been a need to rebuilt the cylinders on these old bike. My new to me 81 has OK brakes, but not as good as my 1977 KZ1000. When I got the Wing I replaced all the pads. All the rotors are well within spec. I also replaced the brake fluid and bled them properly. I have no signs of leaks around the calipers or the MC's however I need to use quite a bit of "squeeze and foot" to slow her down rapidly. I attributed this to the fact that it is a big heavy bike and I am a big heavy person and that's just the way it is. But when I see all these MC rebuild kits I'm wondering if rebuilding would improve my overall braking or should I put my money in new brake lines, calipers etc? Thanks.

 

[dan filipi]

If the MC's have never been rebuilt then it's just a matter of time before the seals start leaking past.

What usually happens is when applying the brake the lever or pedal will fade away, that's the seals leaking past.
External leaks are not common and there is no warning this will happen so it's a good idea to rebuilt them.

SS lines are a great improvement. You may have to replace the rubber lines also since they're almost 30 years old.
Mine were swelling and SS improved the "feel" but didn't lessen the pressure needed.

 

[mcgovern61]

Stainless steel brake lines will stiffen up your brakes and will help apply more pressure. After 30 years since new, it is a good idea to rebuild the MC's to replace the rubber seals......they really do not last forever. (Plus, when you do open up the MC, you often find things you did not expect to be there :mrgreen: ) Same goes for the brake calipers....rubber seals do not last forever ....and.....it really isn't hard to rebuild any of them.

As far as hard to stop, the '81 has single piston calipers that were changed to two piston calipers in '82 on up. The Goldwings started out as naked Standards and Honda added bags and such as the brand grew. The extra weight did add up and ya needed a little more braking power.

I can only speak for my bike....when I brake, I use 60% front and 40% rear and I can come to a halt real quick. If I use front alone...I need almost everything I can give to stop the bike from high speed. The braking system is designed to use front and back together. Last thing...If I jam both at the same time 100%.....the bike will skid real easy!

 

[mcgovern61]

Did it again Dan.....same info...same time! :smilie_happy:

 

[dan filipi]

Did it again Dan.....same info...same time! :smilie_happy:

Its all good Gerry.

 

[Jcol]

Thanks for the quick replies. I'll get the kits for both front and rear and let you know it goes.

 

[dan filipi]

Thanks for the quick replies. I'll get the kits for both front and rear and let you know it goes.

Check your brake lines over carefully. I had a little bubble in one of my fronts, not good.

 

[Jcol]

Thanks Dan - I will recheck my lines again. I did go over them when I changed out the fluids but you never know. My brakes are not mushy, nor does the lever keep going down indicating a seal issue with the MC. The rear just has a little more travel then I would ike and overall braking action requires a good firm pull. I can lock up the rear at about 30 mph but I don't want to run that test at any higher speed and I don't think I would try to lock up the fronts at any speed.