Front Master Brake Master Cylinder

[SIR tricky]

Maybe it's time for a rebuild....

[aspengold]

Nice article tricky. The pics are great. This may be on my list as I work my way from back to front. I know the rear rotor is bad, so I started there after getting the starter problem fixed. EBC Rotor and EBC Organic Pads on order. Thanks to the lead form this forum.

Bob

[Guest]

I rebuilt both the front master and clutch master on my 84 std. I filled with fluid and pumped the handle for 10 minutes. I cant get a drop of fluid out of either reservoir. What do I do or am I doing wrong?

Thanks!

[Ranch55]

I rebuilt both the front master and clutch master on my 84 std. I filled with fluid and pumped the handle for 10 minutes. I cant get a drop of fluid out of either reservoir. What do I do or am I doing wrong?

Thanks!

I'm going to ask a dumb question......
Are you also opening the brake caliper / slave cylinder bleed screws on the pump strokes, and closing the bleed screws before the release strokes ?

I just gotta know and be sure .......

[SIR tricky]

If your doing the above and still having problems drape a few rags under the master cylinders and release the banjo bolt slightly, pump and tighten to make sure there is no air trapped in the master cylinder.

[JerryH]

Anyone use a MityVac for bleeding Goldwing brakes? I have one I use on cars, works great. Never really needed it on a bike, so far. Will see how it goes when I get to the brakes. I also have a little cheap gadget I bought at Pep Boys a long time ago, it is a piece of clear vinyl hose that goes over the bleeder screw, the other end has a ball check valve in it, you can pump fluid out, but air can't get back in. Keeps you from having to juggle pumping the brake, opening and closing the bleeder screw, and keeping the master cylinder full all at the same time.

[bs175dths]

Did you prime the master before trying to bleed?
We all know a large enough air pocket in the cooling system will move through the system until it gets to the impellers, then the impellers will just spin in the pocket of air. Since no water is circulating, the vehicle quickly overheats.
Similar with clutch/brake masters. After a complete rebuild, the master needs to be primed or all the pump will do is move through the trapped air.
I usually bench prime but if it is already on the bike I would protect the bike with rags so as not get any fluid on painted/chrome surfaces.
I would completely remove the banjo bolt and hose from the body of the master.
Lightly place your finger or thumb over the banjo bolt hole, with the master full of fresh fluid, compress the lever allowing the air to escape past your digit, hold the compressed lever and seal the banjo bold hole with your digit, now release the lever.
Doing this a few times should prime the master.
Once you are sure you have fluid flowing, reattach the banjo bolt and purge the system of air and old fluid.
This shouldn’t take too long.

Once done, test the lever pressure and check for leaks.

I don’t think I need to tell you what the next test/step is.

Good Luck

[garyft]

I don’t think I need to tell you what the next test/step is.

Good Luck

Drink a beer?

[tonyc57]

Inspired by this thread I ordered a brake master cylinder kit for a GL1200 DE/DG but I've got a 85/86 Interstate and it won't fit. What do the letters AE/AF/AG/AH and DE/DG mean ?

[bs175dths]

The joys of ordering on-line……

I don’t know what the designators signify. Give the parts house where you ordered the part a call. Have your Vehicle Identification Number handy. There are two numbers, one on the frame and one on the engine. (should be somewhere on your ownership papers too) Have BOTH readily available when you call.

There are some on-line parts houses who break vehicles down by their Vehicle Identification Number or VIN. It is always best to order per the VIN. As an added precaution when I am unsure about a part (or if I just want to avoid this kind of situation) I will call or order in person.

I work at a friend’s auto repair shop (part time) and we will order by VIN just to make sure we get the proper part(s).

In the case of your bike, some parts are interchangeable with the 1984 and fewer with the 1986 so you will need to be sure when part ordering on-line.
For me, a phone call is worth the time.

Good Luck.

[tonyc57]

Curiouser and curiouser ! Given the wealth of knowledge on here I'm surprised this question is proving so difficult. I've checked my ownership document and theres nothing in my VIN number that matches the above designators.
I know that those letters are commonly used over here (UK) by parts suppliers to differentiate between GL1200s.
Given the kit for the DE or DG bikes doesnt fit my imported (from US) 85/86 Interstate mine must be one of 4 others ie. AE-AF-AG-AH.
Trying to solve the conundrum another way - can anyone tell me a GL1200 engined Wing that would have had a different sized brake master cylinder from most other GL1200s?

[goldwingrider]

When rebuilding, I have a service manual and nowhere can I see which direction the rubbers need to go. Does anyone have a diagram showing this? The Packaging did not have any paperwork with it. Can anyone please help?

[SIR tricky]

Never had one apart yet...... I change my fluid every two years.

If your talking about the cup's they look like they are wedge shaped if looked at side on, the widest part would face toward the direction you require the fluid to push.

[goldwingrider]

Never had one apart yet...... I change my fluid every two years.

If your talking about the cup's they look like they are wedge shaped if looked at side on, the widest part would face toward the direction you require the fluid to push.

Thanks Tricky your diagram worked fine I had one of the rubber backward, after I changed it everything worked fine.
I appreciate your help

[seabee]

Did you prime the master before trying to bleed?
We all know a large enough air pocket in the cooling system will move through the system until it gets to the impellers, then the impellers will just spin in the pocket of air. Since no water is circulating, the vehicle quickly overheats.
Similar with clutch/brake masters. After a complete rebuild, the master needs to be primed or all the pump will do is move through the trapped air.
I usually bench prime but if it is already on the bike I would protect the bike with rags so as not get any fluid on painted/chrome surfaces.
I would completely remove the banjo bolt and hose from the body of the master.
Lightly place your finger or thumb over the banjo bolt hole, with the master full of fresh fluid, compress the lever allowing the air to escape past your digit, hold the compressed lever and seal the banjo bold hole with your digit, now release the lever.
Doing this a few times should prime the master.
Once you are sure you have fluid flowing, reattach the banjo bolt and purge the system of air and old fluid.
This shouldn’t take too long.

Once done, test the lever pressure and check for leaks.

I don’t think I need to tell you what the next test/step is.

Good Luck

Here is a link with pics and a video to better understand the procedure.
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