Clutch Issues... Help Needed... 1987 HJ61 (1 Viewer)

[HueyDriver]

Issue: Clutch slipping on 1987 HJ61 with h55

I have had the cruiser for a couple years now, and was told before purchasing the clutch was recently replaced (don't know about pressure plate/flywheel etc..). Noticed after driving on the highway for 2 hours (almost home) the clutch seemed to slip in third gear... RPM's would go up but very slow acceleration. Really weird feeling. Got home and let it sit overnight... drove it next day for 30 minutes and drove fine. Few days later drove it to work 30 min away, and on the way back got stuck in traffic. All gears started slipping... very slow acceleration but made it home. Once I got out I could smell something that hinted of clutch.

Then the truck sat for 2 weeks while on my family vacation. Came back and was able to pull it out the driveway to move my vehicles around.

I dove into the FSM.

Under clutch pedal free play insufficient on CL-3 is below:

I have a booster. My clutch pedal height was at 5 inches... I adjusted the booster air valve stroke point nut on the rod going into the master (cranked the fork out a handful of turns) and retightened the pedal height nut. Extending the fork is the only way I could get my pedal to come forward. She now sits just over 7 inches as per spec. About an inch past my brake pedal. Pedal free play and air valve stroke seem to be within spec as well.

Now when pulling her in and out the driveway, Clutch engages at the very top of the pedal. Example, after putting it in gear and releasing the clutch to move forward, it grabs at the very top of the pedal almost to the point where my foot is off it. I am wondering if this is part of the issue?

Clutch has always felts soft since I have had it, but the way it feels hasn't changed since I have owned her and since the issue arose.

No leaks on master or slave anywhere to be seen. Additionally, I do not have a clutch inspection plate on my bell housing as seen here (missing a bolt…its in the mail now) so I am unable to inspect my clutch. There is a drip of oil seen below, but not enough to warrant showing up on my garage floor:

I have a shot below of my slave attached also. There are mentions online that I should have this adjusted correctly, but I am unable to locate how to do this in my FSM.

Thoughts on what my next steps should be, short of pulling my transmission and looking for rear main leaks and inspecting my clutch? Thanks.

 

[HueyDriver]

Should I have spun the rod going to the booster (if I even can) instead of spinning the fork to adjust the pedal height? Or does it matter?

Also, here is a picture of an early 60 series slave which is different then mine and has the adjustable rod for the fork.

 

[relaxedcruiser]

Difficult to troubleshoot from the distance but it seems to me that your hydraulic system can't release fluid into the reservoir when it gets hot.

To simply check - check the level of your fluid in the reservoir, maybe mark it with a pen, then try to push the clutch release lever (your slave cylinder rod is poking right into it) back into the slave cylinder.
Don't push far but slowly about 2-3 mm if that is possible and the level in the reservoir has risen - that's fine. Your system can release fluid back into the reservoir.
If not - then the adjustment of your clutch pedal / rod in relation to the master cylinder needs adjusting.

A very important fact in all hydraulic clutch (and brake) systems is that the rod which operates the master cylinder maintains a tiny bit of freeplay towards the piston while in rest position. This enables the piston in the master cylinder to retract fully. In this position a tiny equaliser hole is open and links the hydraulic system with the reservoir and enables the system to release fluid when warming up and vice versa when cooling down.
Of course your problem may be somewhere else including a stuck or sticky master or slave cylinder or simply a worn clutch.
But those are the things I would check first. Quite often I have seen wrong adjusted clutch systems in my life.
My 2 cents
Hope you have found the issue by now.

 

[HueyDriver]

New Aisin master and slave are in the mail. I don’t know how old they are, but figured I would replace them when troubleshooting and bleed the system while I am at it.

Additionally, I am going to try and see if I can remove the boot for the clutch lever and get my wire camera inside to inspect the clutch disc.

I will report back.

 

[HueyDriver]

Both came in the mail, but this area on the master looks like it is deformed. Anyone else confirm if it’s supposed to look like this?

 

[relaxedcruiser]

Do you mean the black spot on top of the machined end ? It looks to me that the cast there was actually not as large as it should have been. So after machining this slight uneveness shows with intact paint. If this is the only part there is nothing to worry about. Is this genuine Aisin ? They will have a quality control which won't let the part through if not 100% up to working order.
Be super correct with checking / adjusting the rod to piston clearance.

 

[HueyDriver]

It is Aisin. Didn't want to take any chances so I have a new one coming in the mail and this one is being returned.

Is the how to for adjusting the rod to piston clearance in the FSM? If it isn't apparent by the picture, my model has the clutch booster.

 

[relaxedcruiser]

Yep, that is clearly described there.
As I see it they want to make sure that the pin of the booster is just touching the piston without moving it. That would make sense.
You don't want to push the piston as it will start to pump fluid down to the slave cylinder and will then not allow fluid to freely equalize in and out of the reservoir.
When I got my 60 it has a awful loose clutch pedal feeling and action. Turned out to have, can't remember exatly - 2mm or so play. Reduced that to zero and that's fine ever since.
I have to correct myself from the above post where I said it needs a tiny bit of freeplay - this will be correct for the pedal side of the clutch booster and any other master cylinder - pedal/lever application w/o a booster.
Hope you have a good clutch again soon !

 

[HueyDriver]

New clutch master showed up with the same issue. I find it hard to believe that Aisin would send me 2 defective ones? This what they all look like now?

@relaxedcruiser, seems like it may not be an issue you say?.. anyhow, the Cruiser has been down 2 weeks now so I’ll try and install it.

 

[relaxedcruiser]

Oh no...
The raw cast seems to have the same imperfection through that batch.
I would use it, no worries - the action takes place in the cylinder and that rubber seal behind it is not affected. In my opinion this is a cosmetical imperfection.
Hope that you can cruise soon !

 

[HujSGory]

Are your front brakes releasing fully? got a temperature probe to stick after the clutch issue reappears?

 

[HueyDriver]

I went to swap the slave cylinder and it was leaking fluid under the boot. Swapped it out for the new one, new master installed no issues, and bled again.

Drove it up and down the street, only time will tell if that solved it.

Thanks for the help all. Here is the new one as I am installing it.

 

[Godwin]

I went to swap the slave cylinder and it was leaking fluid under the boot. Swapped it out for the new one, new master installed no issues, and bled again.

Drove it up and down the street, only time will tell if that solved it.

Thanks for the help all. Here is the new one as I am installing it.

View attachment 3325343

Clutch fork boot is not installed properly. The lower rubber ring should be inside the bellhousing with the upper rubber ring flush to the BH. As it is there will be a gap around the base of the boot and debris can enter the BH.

 

[HueyDriver]

Clutch fork boot is not installed properly. The lower rubber ring should be inside the bellhousing with the upper rubber ring flush to the BH. As it is there will be a gap around the base of the boot and debris can enter the BH.

Yep, I took it off to fish my wire camera inside to inspect… couldn’t really see anything inside. Funny enough, it was a pain in the ass to get the boot back on and actually the hardest part!