Rear Master Cyclinder Rebuilding

[kajunmisfitt]

, Hello,
I have a 1985 GL1200 Aspencade and I went on a ride and when I tried to use the rear brake it only would go down with no pressure to make the rear tire to come too a stop. It has been sitting for a few years and I have had it for a little over a year. I have had the carb's pulled and rebuilt. So I am thinking if I pulled the rear master cylinder and going through it then I might be one step ahead. But I am not sure since I can't find anything on rebuilding the rear master cylinder for this year of Goldwing. I was hoping I could find a video to see what I am getting into before I pulled it off the bike. Any help or thoughts would be very much be appreciated.

[DaveO430]

The process is the same as an 1100 viewtopic.php?f=11&t=57 just the removal is different. Have you tried bleeding the brakes?

[simon609zp]

Just been through exactly the same thing with my 1985 Aspencade that had also sat for a number of years. Rear master cylinder rebuild takes a whole lot less time to do than to get it off. Take the floor board off, disconnect the brake pedal at the pedal, take the bolt out that holds the reservoir and empty that into something, remove the 2 hydraulic lines on the top, remove the 2 bolts that hold it on and and then feed it backwards past the shock to get it out. I had no rear wheel on mine at the time which may have helped me.

The only other tricky bit is getting the C clip out - you need the right tool to do that. When you pill the piston out, do it slowly an a piece of cardboard and note or better still take a picture as it comes out. There are only a few pieces.

The bleeding takes a while. Do the right front caliper first (linked brakes remember) and then do the rear. Lots of DOT 4 and keep pumping the pedal until the fluid comes out of the bleed valves.

Good luck

[kajunmisfitt]

I have not had the time since the bike is at a shop being held for work done on my car. But anyway the front brake are working fine, when I push the rear pedal down it goes all the way down no pressure. It stay that way when I pump it up and down a lot, no pressure. I am just getting into the brakes because my 84 has some issue at the moment, so that is why I am wondering if I should just rebuild it, no fuss no muss type of thing. Since I haven't really done any brake stuff just changing the pads. Thanks

[simon609zp]

Like I mentioned, the brakes on these things are like nothing I have experienced before (I am new to Goldwings) The hand lever only operates the left front caliper, the foot pedal operates the right front and the rear at the same time. When you disconnect the brake master cylinder (and get air in it) you will need to bleed both front right and rear calipers. The fronts are labeled as if you were sitting on the bike - so the right front is the same side as the rear brake master cylinder is on. Hope you get your bike back soon - It's riding weather!!

[simon609zp]

But yes - rebuild it anyway - its 33 years old. The kits are $30 or so online. My rear caliper was seized as well so had to rebuild that too. All good now though

[MikeB]

Your problem may be that the fluid needs to be changed. I'd try that first if it was me.

Some friends and I worked on an '84 GL1200 last winter. One of the things that needed to be done was a rear brake master cylinder rebuild because it was leaking fluid from the master cylinder.

The only real issue with removal and replacement of the master cylinder was getting to the metal line nuts. The flare nuts were just about frozen in place. Trying to use a standard open end wrench would only round off the nuts. Access is tight and standard flare nut wrenches are tough to get into that tight a space and still be able to loosen the nuts. I modified a standard 10 mm flare nut wrench to do the job.

I cut the end off the wrench, bent the shaft 90 degrees and then welded the pieces back together. Worked perfectly.

[kajunmisfitt]

Well,
I found something that may have some bearing on what is going on here. I have ask on Facebook but noone has just come out and said "yes" or "no" to my question which is "ARE THE CALIPERS INTERCHANGEABLE FOR THE GL1100 and the GL1200'S". I have a set of caliper's for a 82' GL1100, I had before I bought this 84 model. They look so much alike, I have not put them side by side "yet". But If they can work then it will save me a ton of misery in doing a over hall for this GL1200 front brake system. But the 85 is a different matter all together. So any help y'all give is very much appreciated. This area is an area I really did not normally do myself because of how it would affect everyone around if it is done wrong or if you have a failure while riding, Not into watching people get hurt if I have done something wrong, BUUUUUTTTT KNOCK ON WOOD so far everything has went well so far !!!!

[DaveO430]

Well,
I found something that may have some bearing on what is going on here. I have ask on Facebook but noone has just come out and said "yes" or "no" to my question which is "ARE THE CALIPERS INTERCHANGEABLE FOR THE GL1100 and the GL1200'S". I have a set of caliper's for a 82' GL1100, I had before I bought this 84 model. They look so much alike, I have not put them side by side "yet". But If they can work then it will save me a ton of misery in doing a over hall for this GL1200 front brake system. But the 85 is a different matter all together. So any help y'all give is very much appreciated. This area is an area I really did not normally do myself because of how it would affect everyone around if it is done wrong or if you have a failure while riding, Not into watching people get hurt if I have done something wrong, BUUUUUTTTT KNOCK ON WOOD so far everything has went well so far !!!!

If the 82 was an aspencade they will fit, the difference being the inside width.

[kajunmisfitt]

Yes they were/are, thanks I hope your right

[Charlie1Horse]

Look up both bikes on partzilla.com and match up the part numbers. That will tell you if they are the same.
Russell

Those who say it cannot be done should try not to interrupt those who are doing it.