Stiff Clutch in a GM 4106

Jax DeBusk · April 07, 2015, 03:51:47 PM

Hello everyone. I seem to have a bit of an issue with my clutch being incredibly hard to push down, and requiring a lot of effort to operate. Now I do want to start off saying my legs aren't wet noodles, I can operate the clutch, I'd just really like to know how to make it easier. I hear some people saying the 4106 clutch should be very easy to use, and I'd like mine to be like that as well.

I have greased the fittings for the pedal under the drivers seat, And just about every fitting I could find in the engine bay. Including the one underneath the transmission where the clutch attaches.

I also have tried tightening the bolt that has two springs for what I guess was the spring assist

Any help would be greatly appreciated. I believe some bushings, or maybe some pins are worn out from 51 years of double clutching.

Thanks!
-Jax

RJ · April 07, 2015, 04:50:31 PM

Jax -

Do you have both the shop manual and the shop manual supplement? Directions for adjusting the clutch are in both books, with the better description in the supplement.

You have to start up front and work your way back, basically.

FWIW & HTH. . .

OneLapper · April 07, 2015, 07:30:14 PM

I've been told by other 4106 owners that the clutch on there bus is as pleasant as a VW clutch. Not mine!

A couple years ago I install a new engine and went through the clutch assembly. When I pull the old pressure plate apart I found every fourth spring was missing. Huh? Well, that wouldn't do, so when I reassembled the clutch with new components I put ALL the pressure plate springs in it. Yikes! It's so stiff that my 125lbs SO literally needs to pull up on the steering wheel to get enough weight to push it down. Turns out that Kelley Transport who owned this bus pulled out every 4th spring to make it easier on the drivers.

I have adjusted my clutch to the book and rebuilt all the components to the mouse trap. Once it's in, the mouse trap holds it fine, but its very stiff. I don't think I'll ever need to worry about the clutch slipping! The drive shaft is more likely to snap before that clutch slips.

I'm still playing around with a pneumatic system but I don't have it working yet.

Utahclaimjumper · April 08, 2015, 02:22:52 PM

The mouse trap can really GOTCHA if handled incorrectly,, it also can be CORRECTLY adjusted to practically release the clutch by itself.. Red Rider comes in at about 145# with legs the size of my wrist and has no problem shifting like an old (did I say old?) pro.>>>Dan

Jax DeBusk · April 08, 2015, 04:31:41 PM

Thanks for all of the replies everyone. Good to know people are paying attention (:

And no, RJ. I need to buy those if you have links to the product online.

What do I do to correctly adjust the Mouse Trap? I had tightened up the bolt attached to two springs and it semeed to help, but I think somewhere between the pedal, and the Mosue trap there is some loose or rusted rods or cables. Please forgive my lack of knowledge, I'm still a but new to the world of 4106s ad I just became part of it a year ago. (:

Jax DeBusk · April 08, 2015, 04:39:08 PM

Also if anyone has the pages of the 4106 manual they could email me at jax.debusk11@icloud.com I'd be eternally grateful (:

OneLapper · April 08, 2015, 06:53:15 PM

You can disconnect the clutch push rod on the tranny and then move the pedal up and down. If it's stiff, that's part of the problem, but the fact is the double disc setup has some very stiff springs to it.

luvrbus · April 09, 2015, 06:35:29 AM

I have the air assist from a Eagle clutch I am going to install on a 4106 I'll let you guys know how it turns out should be a easy lol I always say that

TomC · April 09, 2015, 08:16:34 AM

Simple solution-Allison Transmission! Good Luck, TomC

Jax DeBusk · April 09, 2015, 08:57:46 PM

Replaced a bushing and a pin, and adjusted the heck out of everything and made it a little easier to push. Not quite a VW, but it is a heck of a lot easier than before.

Also looked under my transmission and realized I have a few empty slots where springs were, Maybe removing every 4th spring is something they all did when in service?

Had my grandpa step down on the clutch while I looked under the drivers seat in that maintenance compartment and saw something interesting. The wood the clutch pedal hinge is mounted onto pulls down when you step on it because it is rotted. That could be an issue with it not being easy to push down.

OneLapper · April 10, 2015, 07:50:10 PM

Quote from: luvrbus on April 09, 2015, 06:35:29 AM
I have the air assist from a Eagle clutch I am going to install on a 4106 I'll let you guys know how it turns out should be a easy lol I always say that

Definitely let us know!

Utahclaimjumper · April 11, 2015, 08:29:00 AM

It would also be an issue if it broke at a bad time!!>>>Dan

kingfa39 · May 10, 2015, 02:51:55 PM

some early 4106 had a air assist clutch, however they troublesome, mechanic I had at the time wouldn't work on it, was slow to respond, the wishbone I had on my other 06 was a pain to adjust , my book did not show how to adjust the thing and I never got it like I wanted it. I did see one however that was easy as any car but the owner was reluctant to help me out, I sold that one too after 25 or so yrs, best vehicle I ever had. never had a break down

gus · May 14, 2015, 11:46:29 AM

There are a bunch of bushings and pins in this system. A little wear at each of these results in a lot of slop.

The bellcrank at the firewall has Al arms that will wallow out when the bushings wear through.

When all these points are badly worn the clutch cannot be properly adjusted.