What's with the Volvo Clutch?
 

Just bought me a Volvo. 530 ISX Cummins, 3:90, Super 40's. Nice truck. When I test drove it a couple of times, the clutch seemed really high, like at the end of it's adjustment. I asked the salesman to have it adjusted and the clutch checked before I bought it. He did and then informed me that it was an air over hydraulic clutch and the clutch had lots of life left. Seemed weird but whatever. It was working fine until today. First I was loading grain (super-b)in a farmer's field and went to pull ahead while loading. Released the clutch and nothing. I pushed in the clutch again, checked that I was in gear then released the clutch and away I went. I should note I was nearly loaded and in soft ground, but I got out no problem. Later today I was FULLY loaded and then some, likely a good 10-12000lbs overweight and I went to pull ahead on a solid driveway. I released the clutch and nothing, no grunt or squeal. Nothing. So eventually I decided to split the trailers. I pulled out with the lead no problem. Drove it home then came back for the pup. (That doesn't seem like the most efficient way to pull super-b's!) My question is are these clutches self regulating or something? Can it sense too much torque? Can I adjust the clutch? HELP?:confused:

Is this an autoshift?

The clutch is completely out of adjustment.

Just because it is hydraulically actuated doesn't change the fact that the pressure plate needs to be kept adjusted to compensate for clutch wear.

Don't keep trying to use it that way or the clutch discs, pressure plate, flywheel and center plate will be ruined due to excessive heat caused by slippage.

Hopefully there is still some adjustment left, and the clutch is not already at the end of it's lifespan.

Remember - these clutches must be adjusted at the pressure plate NOT at the external linkage.

Edit to add:

I dug up an old post where I explained the clutch adjusting procedure, should you decide to DIY:

http://www.classadrivers.com/forum/t...tml#post217175

No it isn't an auto shift.
Thanks for the adjustment tips. I just assumed when the dealer said it was perfectly adjusted he new what he was talking about. I'll check it out and get back to you.
It's funny. Since I found this website this is the first place I go for answers. I tend to trust other truckers a heck of a lot more than anyone else. Thanks again!:bow:

Talk to the Volvo service shop about your problem. Do not talk to the guy that does the writeups, odds are he knows very little about the trucks. Talk to an experienced VOLVO mechanic. Those air assisted hydraulic clutch setups look nice, but man I bet they can be tricky!

Did the truck try to move at all when you released it? It could also be the slave cylinder sticking. I had that problem.

Yes, the truck did try to move a bit. Another strange phenomenon I didn't mention is that sometimes the clutch releases at the top of the peddle, sometimes at the bottom and sometimes half way in between. I've also had it where I could barely get it out of gear. So what you mentioned about the slave cylinder makes some sense. I'm phoning Volvo in the morning. Thanks again and I'll keep you posted.

The volvo I was in did this from time to time, let off the clutch and nothing at all, would have to floor the clutch and let it back out. Didn't do it a lot but it did do it from time to time. Also had it from time to time when floating I would go into a gear but nothing, would have to press the clutch in and let it back out, was very annoying when it did that. Usually did it going from 4 to 5 (low side to high side), but it has done it to me in a few other gears as well. But I am not in that truck anymore so I don't care about it any more :)

I bet this is a solo clutch (self-adjusting).

If your clutch has been misadjusted, you will have the same concern, consistently. Here's an example - each time I apply full engine torque when pulling a loaded wagon, the clutch seems to slip or chatter. Or, another example - when i fully depress the clutch pedal, I cannot get into low because the gears are grinding. A misadjusted clutch DOES NOT cause the clutch to do an INTERMITTENT, FULL hang-up (no clutch engagement when you release the pedal).

The reason techs always blame clutch adjust is because it is one of the few things you can do to a clutch without dragging the tranny out... and, the adjust is commonly done wrong in the field.

Well boyz, sorry it took so long but I think I've got it figured. First of all, yes it is a solo clutch. (By the way if any of you have more info on those please share!)
As far as the clutch sometimes releasing goes I took the truck to a former Volvo mechanic(opened his own shop) and explained my problem. He crawled under the truck for 2 minutes and found the problem. Apparantly in these air over hydraulic slave cylinders, as the fluid pushes the cylinder a valve opens to allow air in to assist. Then when the clutch is released an exhaust valve opens to relieve the air pressure. This truck sat for nearly a year before I bought it and it turns out the relief valve was sticking thus not allowing the air to escape. Sounds weird but I haven't had any problems since and have even "accidentally" loaded a little heavier than legal on a few occasions with no troubles. Thanks y'all for the help.

how did u fit it my clutch slips when its hot ,i have to bleed fluid every time