Clutch Slave Cylinder overhaul

[wiredgeorge]

I was on my way to lunch after church on our 1997 GL1500A Roadsmith trike. Shifting was growing progressively harder and when I had to stop, the trike wanted to creep. I knew immediately that I had a clutch issue. After lunch, I opened the master cylinder and it was almost empty. I refilled and bled using an article here on this site for guidance after purchasing a MityVac. It was a snap and the clutch worked perfect but I knew that the fluid must be going somewhere. So I decided to rebuild the clutch slave unit.

Of course, the first issue was getting the trike up high enough to get underneath. I won't bore you with those details but once up in the air, here is what I did:

Someone had mentioned it might be dripping out a small relief hole... that is EXACTLY what it was doing. Just couldn't see the dripping which was mostly dry until the trike was up in the air. The bottom of the clutch cover was covered in old but mostly dry brake fluid. The hardest of this whole job is cleaning the old brake sludge out of the opening where the slave cylinder seats. The old brake stuff had turned to gel and then gotten real dirty.

Here is what you do. FIRST (after getting your trike or bike lifted where you can get under) loosen the M6 bolt that holds the pipe with the bleed fitting. Then remove the M8 banjo bolt where the clutch line comes down from the lever. It is pretty tight as it holds a couple crush washers and is easier to loosen before removing the slave cylinder. You might want to buy some new crush washers to be professional but I re-used mine since I had not bought them. I think they are a standard auto parts item (M8 crush washers). Then remove the three bolts holding the slave cylinder. It doesn't just come loose... you have to squeeze the clutch lever a couple times. Have a drip pan under the slave cylinder and have some rags handy. Once the piston pushes out the slave cylinder, it comes right out. Take it to a bench, clean it and install the new rebuild kit. It is K&L P/N 32-0150. It includes the small seal that goes around the piston, the larger seal that goes around the main body, a replacement spring and a new dust cap for the bleed valve. To be honest the seal in the clutch cover that the piston fits into in the clutch cover looked pretty beat up. It is Honda P/N 91204-MB0-013 Oil Seal (8x25x8) (Arai). If doing the job again, I would not only have four new crush washers (2 for the oil pipe that connects to the bleed valve and 2 for the oil line coming down from the clutch master cylinder) AND the clutch cover oil seal. It would not be hard to remove or replace as it is just pressed into place. Install the seals with some brake fluid to lube them. I used DOT 4 as called for. Refit the parts as you took them off and drop the trike/bike and bleed the master cylinder. I used my MityVac and it took about 5 minutes. I will ride the trike a bit then stick a mirror down below the clutch cover to see if there are any new signs of brake fluid on the bottom of the cover.

[wiredgeorge]

Made one mistake... the banjo crush washers needed are M10; not M8. Sorry.

[goldwing8754]

If you take the banjo fitting loose first, how are you going to use the clutch to push out the slave?

[Corkster52]

I believe I have a slave issue as well. Will be watching this thread.

[zandersn]

So what is the secret to removing the oil seal? Mine was bad too, but now it is really tore up from trying to get it out and after an hour or more, I don't think I have begun to move it.

[Jenneverett1]

I watched a great video on rebuilding the slave on my GL 1500 SE , but there was no video on the same bike for the master.
I was pleasantly surprised that only the fluid line, 2 bolts and 2 sensors were needed to remove for removal of the master and clutch handle.
The disassembly was done in minutes and my parts will be in on Tuesday ( this is Sunday).

The entire thing

Broken seal pieces

Outer boot

Clutch piston

[Bob380S2]

Thank you for the post especially with the part numbers and the tip about changing the clutch cover seal at the time which I did. The whole job would have been fairly simple but for getting the latter seal out which is a swine. You can't see it without a mirror, and the rubber seal has a metal inner which stoped me doing the usual of pocking a screwdriver through it and levering it out. Instead I spent a couple of hours destroying it to the point that I could get some tiny pliers into it and twist it out. Having done this I realised that the push rod that goes through it into the clutch can in fact be simply pulled out which would have made the whole thing easier I'am sure. So, my tip for the day is, after pulling the slave cylinder of as described, pull out the push rod before trying to remove the clutch cover seal and save yourself a frustrating couple of hours!!! Obvious really, once you know!

By the way, I did all this because I was losing clutch fluid with no obvious signs of why. Once I got the slave cylinder removed I couldn't believe the mess inside it to the point that I was amazed it had worked at all. The seal was completely trashed and the whole thing covered in brown gunge. My bike is 2000 and at 56,000 miles. The clutch fluid loss has been gradual over the last two years but becoming worse and I'd done just about every other seal in the clutch and braking systems so definitely one to keep an eye on and do if in any doubt. It seems that these very same slave cylinders are used on all the GL1500s and a good many other Honda bikes right up to at least 2010 in the GL1800 and Pan European. The seal repair kit I bought was £15 and listed for the 88 - 90 model but the same part number at higher prices is listed for later bikes such as mine and of they course are identical.

[WingAdmin]

By the way, I did all this because I was losing clutch fluid with no obvious signs of why. Once I got the slave cylinder removed I couldn't believe the mess inside it to the point that I was amazed it had worked at all. The seal was completely trashed and the whole thing covered in brown gunge. My bike is 2000 and at 56,000 miles. The clutch fluid loss has been gradual over the last two years but becoming worse and I'd done just about every other seal in the clutch and braking systems so definitely one to keep an eye on and do if in any doubt. It seems that these very same slave cylinders are used on all the GL1500s and a good many other Honda bikes right up to at least 2010 in the GL1800 and Pan European. The seal repair kit I bought was £15 and listed for the 88 - 90 model but the same part number at higher prices is listed for later bikes such as mine and of they course are identical.

If you are having clutch fluid loss, and there is no obvious leak, then make sure you change your engine oil right away. If clutch fluid leaks past a seal in the slave cylinder into the crankcase, it can destroy the engine.

[Bob380S2]

Yes thanks, I read that although I'm pretty sure it didn't make it past the clutch cover seal (which I have changed now anyway although it looked ok) and as another poster said, there is a drain hole under the slave cylinder where it can escape. However I'm going to change the oil now anyway just in case. Should I flush it with something first and if so, ant recommendations?

Thanks to everyone on here - great site!

[wayne perry]

ok I am having a problem reinstalling the clutch slave cylinder. Is there a trick to lining it up with the 3 bolts or am i just trying too hard. I cant seem to get it to turn and go in to line up with the bolt patterns . I have the rod in the cylinder and i believe the slave is going on it but am unable to get it to line up. what is the trick.

[DougEFresh1123]

Hello folks. This winter I am going to be doing the clutch slave rebuild. I have read through the article but since I’m an idiot when it comes to mechanical functions I have no idea were to find the clutch slave cylinder. Based on the picture in the Clymer manual it looks like it is under the alternator and the best way to reach it is to lift the bike and have the center stand up. Is this correct? Any and all pictures would be greatly appreciated.

Thanks - Doug

[Bob380S2]

Hi Doug. I think when I did mine last year I just pulled the alternator out and it got to it though there.

[DougEFresh1123]

Thanks for the info.

I had to replace my alternator in September, and the replacement is a bit bigger and was a tight fit.

After getting my son involved and using a flashlight I found it and I will be lifting the bike up off the ground and securing it via straps and jack stands.

Thanks - Doug

[dingdong]

You do not have to pull the alt. in order to work on the slave cylinder.

[Bob380S2]

Dingdong nobody is saying you have to pull the alternator - only that I did it that way, which in the absence of a bike lift worked for me (as I recall).