michigan 75b loader de-clutch

[tree_man150]

can anyone tell me the if i am right in the operation of the torque convertor/transmission de-clutching.
after building air pressure if you put the machine in gear and step on the brakes should not the transmission go out of gear so you can scoop or dump with out the wheels turning--thus making it so you don't have to move the gearshift lever into netural?
i'll post a couple pics of the trans valve to see if its what i think it is.
first pic shows airline going into shift lever area--de-clutching?
second shows switch with electric wires at shift lever--de-clutching? back-up lights?
third is switch on brake valve---is this for brake lights--or having to do with the de-clutch
thanks one and all for any info

 

[oldseabee]

The left hand brake pedal is for declutch, the right hand bypasses the declutch. Truck drivers hate it when you declutch and go to back away and the machine rolls into the sideboards before the clutch engages.

 

[tree_man150]

thanks oldseabee- my machine does have 2 brake pedals--but there is a rod that ties them togeather,so when you push on one they both work---one is like a dummy pedal--only one brake valve and its right under the right pedal

 

[oldseabee]

Parts book shows a brake valve under each pedal and in addition the left pedal sends air to the declutch for the forward clutch, no declutch in reverse. Sometime ago there must have been a reason to remove the left valve. Operators manual also describes the brake system with a left pedal declutch.
All the Clark loaders from that era had that feature.

 

[Komatsu 150]

Yep at least once a day the operator would turn to look behind him, tromp on the go pedal and slam into the side of the truck because he forgot to switch to reverse. Those old machine had a pretty big delay before they would engage. I disabled that feature on both our old machines. It also made loading on a tilt deck trailer a fun ride sometimes, stop too soon before the deck tilts and by the time the clutches re-engaged you would be completely off the trailer.

 

[oldseabee]

I think that I see the problem. Is your machine articulated or straight frame. There was a very early 75B straight frame machine that had what you describe and doubt if it had declutch.
I've been looking a 75B articulated machine which had left pedal declutch. Sorry for confusion.

 

[tree_man150]

the machine is articulated
it does not appear that any changes have been made in the brake pedal area.
i just traced the lines- and from the brake pedal valve a line goes to the front of the brake booster into a tee- that goes in the booster- the tee splits off and goes to the little valve that is just behind the shift rods/plungers on the front of the transmission--you can see it in the first picture--
any idea what the electric switch that is on the side of the shift rod/plunger housing might be for?-the one in the second picture

 

[oldseabee]

75B articulated machines had S/N 447A 101 and after GM or 443A 101 and after Cummins and did have left pedal declutch.
75IIIA articulated machines had S/N 409A or B and after GM or 408A or B and after Cummins and did have declutch on either pedal, that turned out to be a problem in some applications so the change was made to the new model 75 B machines to left pedal declutch.
check your serial number to see what you have. a lot of machines were repainted and called B models.

 

[tree_man150]

the manufacture plate on the hood ,left side, right behind the cab reads: model 75GMIIIA serial # 409-b-306 cac---- those numbers match the ones stamped in the frame right side rear half of the machine just below the rad housing----and on the front half by the pivot area.
i guess perhaps i have been thinking i have a B machine when it really is an A.
from some of the pics i have seen it looked like all A machines were straight framed-and b machines articulated.

 

[oldseabee]

Original A straight frame machines were also called series I and had the boom pivot behind the operators area which caused some body parts to be seperated from the owner. They then created the series II straight frame with the boom pivot in front of the operators area. The next advancement was to improve and make the 75III straight frame machine, then they decided to make it articulated and called it 75IIIA. The next change was to the 75B articulated. Then on to 75C.
That is one reason that serial numbers are critical especially when looking for parts.

 

[BrandonTcm75b]

Yep at least once a day the operator would turn to look behind him, tromp on the go pedal and slam into the side of the truck because he forgot to switch to reverse. Those old machine had a pretty big delay before they would engage. I disabled that feature on both our old machines. It also made loading on a tilt deck trailer a fun ride sometimes, stop too soon before the deck tilts and by the time the clutches re-engaged you would be completely off the trailer.

How did you disabled it sir?

 

[Komatsu 150]

How did you disabled it sir?

My machine had hydraulic brakes and there was a slave cylinder in the trans that would do the declutching. I pulled the line and plugged the port at the master cylinder. Loading trucks the declutch was useless as it was natural to pull the machine into neutral after reaching the truck. The only place it was of any use was loading at a stock pile. After filling the bucket those machines did not have enough power to raise the bucket into the pile when in gear.