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Author Topic: Here's a question for all of you double-clutchers.......  (Read 4591 times)

Offline NCbob

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Here's a question for all of you double-clutchers.......
« on: August 05, 2006, 11:30:17 AM »
Having recently had a new and stronger clutch put in my MC5A I'm finding that either old age or not enough pressure to the air assist cylinder is giving me a bit of a problem.  Oh yes, I'm going to jump back on the treadmill and build the legs back up but there's only so much help for what's gone beyond its' years. :-\

Does anyone know if I can boost the pressure on the air assist cylinder and if so...what would be the max it could handle?
Naturally I'd love for it to operate like soft butter...but what I'd like and what I'd get aren't usually even acquainted. ???

Please, let's see if we can come up something of a serious answer...because I already have an idea of what I'm going to hear from the likes of our illustrious Chat Room Moderator and a certain Cable Guy in FL. :-\

Bob
True friends are difficult to find, hard to leave and impossible to forget.

Offline Buffalo SpaceShip

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Re: Here's a question for all of you double-clutchers.......
« Reply #1 on: August 05, 2006, 12:54:34 PM »
Sorry, Bob... all I can currently offer is a non-serious answer:

In the immortal words of Elvis Costello: "Oh Allison, my aim is true."

Again... Sorry :D
Brian Brown
4108-216 w/ V730
Longmont, CO

Offline Happycampersrus

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Re: Here's a question for all of you double-clutchers.......
« Reply #2 on: August 05, 2006, 01:47:34 PM »
Now Brian,

You know at our last secret Allison club meeting we agreed not pick on the other guys ;D ;D

BTW the cooler works great, I can't get the tranny temp above 180. Thanks Brian ;)


Dale

Offline RJ

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Re: Here's a question for all of you double-clutchers.......
« Reply #3 on: August 05, 2006, 02:35:06 PM »
Bob -  Have you adjusted the clutch linkage according to Da Book?

On GMCs, to properly adjust the clutch, you have to start up front and work your way back.

Don't have my MCI shop manual handy, but I wouldn't be surprised if it has something similar.

IIRC, there is a certain angle that the air assist is supposed to be at in order for proper operation, have you checked that?

Don't know if you can adjust the air pressure utilized, but maybe a different (larger) diameter slave cylinder?

HTH. . .
RJ Long
PD4106-2784 No More
S13406 1978 MC-5C Converted
6V71/MT-644
S14947 1980 MC-5C Shell
6V92/HT-740
Cheney WA

Offline gus

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Re: Here's a question for all of you double-clutchers.......
« Reply #4 on: August 05, 2006, 03:13:22 PM »
NC,

Russ is right on,  the adjustments are very important as is the condition of the rod ends and pins. My 4104 had a couple of pins worn more than half through and the rod ends were pretty wallowed out. Once I changed these and went through the clutch adjustment by the book I no longer got the shaky leg when I maneuver into a tight spot!! I don't have air assist either, that would be nice. Your's must be pretty far out of adjustment if it is still heavy.

The whole idea is for all the levers to be at 90 degrees when the clutch is depressed so you have max leverage. It took me a while to figure this out but I'm a bit slow these days.
PD4107-152
PD4104-1274
Ash Flat, AR

Offline pvcces

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Re: Here's a question for all of you double-clutchers.......
« Reply #5 on: August 05, 2006, 05:06:47 PM »
If I recall corectly, there's a pressure regulator that sets the maximum effort that the air assist will apply. You might try to find out if it is doing it's job.

For what it's worth.

Tom Caffrey
Suncatcher
Ketchikan, Alaska
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska

Offline JimW7

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Re: Here's a question for all of you double-clutchers.......
« Reply #6 on: August 05, 2006, 06:40:13 PM »
On my 7, the clutch was getting pretty hard to push down, greased all fittings, not much help, air cylinder appeared to be working, so I started takings things apart. The bearings on the top of the tranny were getting grease, but when I moved the clutch lever, the bearings had worn a groove in them, and the linkage would bind up. It was so tight, I'm surprised nothing broke. I replaced the bearings, adjusted levers to the book specs, and lucked out, it works fine. Hope it is that simple for you, Jim.
1970 MCI 7 serial # 8425

Offline Busted

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Re: Here's a question for all of you double-clutchers.......
« Reply #7 on: August 05, 2006, 11:01:23 PM »
This is an easy one.  Locate the control valve for your air assist slave. Remove the control valve & take it apart. There are (what look like) washers that limit the amount of travel. Remove at least one third of the washers, reassemble & reinstall unit. The supply (air) does not need to be regulated, the valve can easily handle 120psi. The amount (pressure) of air that goes to the slave is limited by the amount of travel of the control valve. (ie if it opens further it allows more air) Play with it until its as soft as you want. We used to call this "hot rodding the clutch" & used to charge a flat fee of $100. to do it. Even with a dual disk & heavy plate you can have it where you can literally depress the clutch with one finger.

Offline gus

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Re: Here's a question for all of you double-clutchers.......
« Reply #8 on: August 06, 2006, 06:37:25 PM »
Bob,

I forgot to mention that you really don't need to use the clutch except for starting from a dead stop.

 I never use my clutch underway and can't tell any difference in the shifting. I clash gears about the same either way!!
PD4107-152
PD4104-1274
Ash Flat, AR

Offline Hobe

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Re: Here's a question for all of you double-clutchers.......
« Reply #9 on: August 07, 2006, 04:26:09 AM »
All you need to do is back off on the set screw and turn the bolt in about 3 turns. Make sure that every thing is greassed up in the front. When you will have the most leg hurt is when there is a bad accident on the Interstate And you are just creaping and need to push it a gillion times. With a bad left leg I got smart and put in a automatic. Never been happer. Fred