MCI 102A3 Air Assist

[Doug1968]

Gentlemen,

Does anyone know if the air assist clutch option is available for my 86 102A3? Am I correct in assuming that this is an option that can be added? Also, is there a big difference in the amount of pressure required to operate the clutch when the air assist is added?

Although my clutch is not too bad to operate I would not like to be stuck in bumper to bumper traffic and have to destroy my left leg.

Any thoughts on adding this option and where I might purchase the parts would be appreciated.

Does this assist mount back at the transmission?

Thanks,

Doug

[Tony LEE]

Don't know about your model but when I bought my 78 MC8 I thought I was going to be in trouble because of old knee problems. Found that there was an air assist that was obviously someone's idea of a joke since it didn't assist anything.
Pulled the cylinder and cleaned the bore and seals and lubricated it and the difference was incredible.

Betty passed her heavy Rigid  licence endorsement (required by law here) in the bus and has no trouble driving it. Well, clutch is OK but she hates the steering.

[luvrbus]

Doug, I would go with a hydraulic far better than a air assist Prevost has a nice system that will bolt up to your transmission.I can send you a drawing of their system by US mail if you like. Ps you don't have to buy parts from Prevost but they are not bad on the price    Good luck

[Len Silva]

Doug,
This does not answer your question but perhaps a different take. I saw a setup on a 4104 (can't remember where or when, or even who) that was quite simple.

It used an electric solenoid, maybe an automotive door lock, operated by a momentary contact switch on the shift lever.  You would depress the clutch and operate the switch.  This would operate the solenoid latch to prevent the clutch pedal from coming back up.  The tension from the pedal held the latch in place until you pushed down on the pedal a bit and it released the latch.

This is not the same as assist but much simpler and I think quite useful in traffic.  I think air could be substituted for electric.

[bevans6]

On my 1980 MC5 the air assist cylinder is at the back, on the side of the transmission.  I'm going to be taking it out and refurbishing it shortly, as it does work, but not all that well.  If your bus has an air assist cylinder but it doesn't help enough, I have toyed with the idea of either feeding it with higher pressure air (if its air is regulated down at all) or with replacing it with a larger piston diameter cylinder to get more boost.  I have heard of putting an air assist cylinder at the front of the bus as well, if you figure the leverage ratios you could put it about anywhere.  the MC5 version works in such a way that it's always pressing hard, but the angle of pressure with the clutch out (pedal up) is dead in line with the clutch operating mechanism, so the pressure does nothing.  As the clutch is disengaged, the air cylinder is pressing at an increasing angle, so it's pressure can have more effect and help press against the clutch springs.  As the clutch is fully disengaged, pedal on the floor, you get full assist.  At the engagement point, pedal up 75% of the way, you get fairly low assist.  So the effect is to help you hold the clutch all the way in on the floor, and not to make it lighter all the way up and down.

Brian