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TRAC Valve Leak & Brake Fluid Mystery
OK, I have two separate mysteries, but I'm gonna put them in the same thread.

Front Brake:

I just did some routine maintenance on my '87 GL1200A this past weekend. Bled the brake and clutch fluid. First I'll rat myself out and say that somehow I skipped a year on this maintenance, so it's been two years since I did this service. (I have no excuse!)

All was good until I opened up the MC reservoir on the hand brake lever. The MC was almost empty! Yikes! I felt absolutely no evidence of a mushy brake lever or any other symptoms on the brake while riding. So, I was surprised to see that. I can also find no evidence of any brake fluid leak anywhere along that entire system, from the MC to the hoses down to the left front brake caliper. So, where the heck did that brake fluid go??? Two years I know, but still it's a sealed system.

Left Fork - TRAC anti-dive Valve:

Upon searching for a brake fluid leak, I found fluid on the speedometer sender unit (Aspencade with digital instruments) at the bottom of the left fork. At first I though, Oh that's brake fluid, but the TRAC valve only has fork fluid in it, so that's not it. It's got to be fork fluid.

Only other thing could be that the TRAC valve is leaking internally OR the bolt in the very bottom of the fork is leaking. I'm taking the front wheel off in the next day or two to replace the front tire, so I'll have a better look soon. If it is a leak in the TRAC valve, I'm concerned.

Can you even get repair parts and/or gaskets for the TRAC valves anymore?

Thanks for any insight or advice.
'87 GL1200A - Black/Grey
'06 GL1800 - Arctic White
'81 CB750C - Blue/Blue
U.S. Navy SWO (1967 to 1976)
Reply
#1 04-27-2015, 12:46 PM,
Yes, the brake (and clutch) systems are closed systems.
Your brake fluid level will go down as the brake pad material wears. So you really don't need to top off unless you are on the verge of drawing air into the system.
If you do add fluid to a system where the pads have worn, when you replace the pads, and compress the piston into the caliper, your brake fluid will overflow at the master with the cover removed. If you don't remove the cover, you won't be able to compress the piston.
So, it is not a big mystery having low brake fluid level and still have great lever pressure.

As far as TRAC, check to be certain it is coming from the TRAC and not from the fork seal.
Check out the link below for available TRAC parts. You might be surprised at what is available.
If what you are looking for is obsolete, try searching the WWW with that part number, again, you might be surprised.

http://www.partzilla.com/parts/search/Ho...parts.html


-Ride On
enjoying the view from the saddle....... due mainly to the people and information found within this site
Reply
#2 04-27-2015, 09:19 PM,
(04-27-2015, 09:19 PM)bs175dths Wrote: Yes, the brake (and clutch) systems are closed systems.
Your brake fluid level will go down as the brake pad material wears. So you really don't need to top off unless you are on the verge of drawing air into the system.
If you do add fluid to a system where the pads have worn, when you replace the pads, and compress the piston into the caliper, your brake fluid will overflow at the master with the cover removed. If you don't remove the cover, you won't be able to compress the piston.
So, it is not a big mystery having low brake fluid level and still have great lever pressure.

As far as TRAC, check to be certain it is coming from the TRAC and not from the fork seal.
Check out the link below for available TRAC parts. You might be surprised at what is available.
If what you are looking for is obsolete, try searching the WWW with that part number,
You again, you might be surprised. You do not have to remove the master cylinder cover to compress the pistons in the calipers. Poorboy

http://www.partzilla.com/parts/search/Ho...parts.html


-Ride On
Reply
#3 04-27-2015, 09:49 PM,
Thanks guys.

I'll have a look at the brake pads when I pull the wheel off for the tire replacement in the next day or two.

Regarding the leak underneath the TRAC valve on the speedometer sender unit, that's the only place there is any fluid and it's not a large amount, i.e. it's not dripping off of the bottom, it's just wet on the surface. There is no fluid leaking from the fork seals. In fact there is no fluid anywhere but on the speedometer sender unit.

When I get the wheel off I'll pull off the fork brace so that I can work each fork slider up and down independently and see if I can feel a difference between the left and right side. If so, I'm probably low on fluid on the left side where its wet on the bottom. If I detect a difference I guess I'll have to flush and refill that fork which will give me a chance to disassemble and check the TRAC valve on that side.

I did check the parts microfiche and I see that you can get the big gasket that seals the TRAC valve housing. I may just buy two of those before I even get started.

Thanks again.
'87 GL1200A - Black/Grey
'06 GL1800 - Arctic White
'81 CB750C - Blue/Blue
U.S. Navy SWO (1967 to 1976)
Reply
#4 04-28-2015, 05:08 AM,
OK, I found the "leak" that made the speedometer sender unit (Aspencade with digital instruments) look all wet like it had brake fluid or fork oil on it.

It was not brake fluid or fork oil.

The speedometer sender unit has an o-ring seal where it attaches to the speedometer gear unit on the front wheel axle. That o-ring was not completely sealing. So, the wet look on the speedometer sender unit body was nothing more than the axle grease that lubes the speedometer gear bleeding past the o-ring a bit and coating the outside of the speedometer sender.

Great outcome for me. No fork dis-assembly or rebuild required.

***
'87 GL1200A - Black/Grey
'06 GL1800 - Arctic White
'81 CB750C - Blue/Blue
U.S. Navy SWO (1967 to 1976)
Reply
#5 05-01-2015, 11:23 AM,
Cool..........

Now go for a ride!

-Ride On
enjoying the view from the saddle....... due mainly to the people and information found within this site
Reply
#6 05-01-2015, 03:21 PM,
just replaced the fork seals and found a leak on front forks,the copper gasket on the fork drain plug is leaking,clean it up and check there
1987 Aspencade 129K
1986 SEI 93K
2014 Tri-Glide HD 17K

Hancock,MD
Reply
#7 05-01-2015, 05:38 PM,


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