Trunnion stand question

[ranchhopper]

Did mack make several widths of trunnion stands I have a chance to get a nice cut off with the camel back suspension I have been wanting to swap out my existing suspension to camel back.I have found most were made for the double frame application and when put into a single frame truck they shimmed the quarter inch gap on either side to make them fit. I have an aluminum frame with 3/4 inch gap on either side of the stand can that much gap be shimmed maybe weld some stock to each side of the stand or make shims out of 3/4 aluminum plate. Since there wont be any room for twisting with shims in place can anyone see a problem with me putting it together this way?

[storkmack]

I don't see why it wouldn't work. Like you said weld some stock in there to take up the difference.

[ranchhopper]

Brad other potential problem may be that the frame being an inch and a half wider may interfere with the movement of the springs and brake chambers.

[41chevy]

Brad other potential problem may be that the frame being an inch and a half wider may interfere with the movement of the springs and brake chambers.

Here is from my MACK parts Guru at Gabrielli

Normal MACK Trunion shafts are:

3 1/2" O.D. x 48-3/4" Lg., 3-5/16"-12 Thread , P/N Model SS44/SWS57 85QK251, 85QK249

4" O.D. x 50" 3-7/8"-12 Thread w/4 each 5/8"-18 Threaded Holes , P/N 85QK355, 06283, MB8

4" O.D. x 50" 3-7/8"-12 Thread , P/N 334-499A, 85QK336, MB2

Basic chassis width is 32 1/4 inside to inside frame rails, no info if single , double or triple rails. Basic shim kits to make up 1/2 to 3/4 total are 1/4 or 3/8 in sets of 4.

First shaft # is for 3 inch wide springs, second two are for 4 inch wide springs.

[ranchhopper]

Here is a picture of an aftermarket trunnion stand looks like a lot of shimming to install this I just didn't want to buy something I wasn't going to be able to use I believe my frame is 34 inside rail to rail.

[41chevy]

There a 2 different trunion shaft widths from 50 inches to 48 3/8. standard chassis is 32 1/4. Standard shim kits are 1/4 inch (X2) to make up a 1/2 inch and 3/8 inch (X2) to make up 3/4 inches.

Have your dimensions and call them.

Truck Components Online

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Tampa, FL 33604

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Phone: 1-813-933-1166

[ranchhopper]

Thanks I will check it out but I would be willing to bet the 50 inch trunnion tube is for aluminum frame trucks.

[41chevy]

Thanks I will check it out but I would be willing to bet the 50 inch trunnion tube is for aluminum frame trucks.

It also uses 4 inch wide spring packs.

[Vladislav]

I see no trouble if you need some shimming, no grinding

[j hancock]

I looked at a brochure for an aluminum chassis and it shows a 33.5" inside measurement.

http://www.bigmacktrucks.com/index.php?/tutorials/article/86-rw-superliner-brochure/

[ranchhopper]

You beat me to it I was looking for that brochure Im sure the placement into the frame and shimming isn't going to be a problem.

[41chevy]

I'd use 3/4" Aluminum plate for each side as a full run spacer and pick up a set of 1/8" shim packs if needed.

[ranchhopper]

I was going to get a plate for each side I don't think those shims cover enough surface area.

[41chevy]

I was going to get a plate for each side I don't think those shims cover enough surface area.

I'd only use the shims for the minimum adjustment if needed no more, the shims are/were originally made to fit the OEM Trunion mount plates

[ranchhopper]

I think the original idea for the shims is so they could use the same stand in single frame trucks they built it out to fill the space where the inner frame rail would have been.

[41chevy]

You beat me to it I was looking for that brochure Im sure the placement into the frame and shimming isn't going to be a problem.

Makes perfect sense.

The 4" dia shafts, one would be for 4 inch camel back springs and the other is for hard bar or the 4 inch springs that has the the 4 bolt ends. Paul

[Mcrafty1]

Here is a picture of an aftermarket trunnion stand looks like a lot of shimming to install this I just didn't want to buy something I wasn't going to be able to use I believe my frame is 34 inside rail to rail.

I have one of these stands/tubes installed in my 86 R model double frame.....it is (as was explained to me) made as narrow as it is for the sole purpose of being able to install from under the truck as opposed to removing the body and/or everything in between the rails from the stand back and replacing with the original type stand. The only shimming required (in my case) was the pieces shown in this picture, The bolts are bigger than original and the existing holes in the frame need to be reamed so they'll fit. I have a dump on my truck and this made so much more sense to me than the other option of removing everything to replace the stand. It is also very stout and I've no doubt it will hold up equally as well as the factory stand and in the sense that no corrosives can accumulate in the stands they should never rot out again which is what happened to mine. I replaced the stand, both spring saddles and everything within, 4 gripes and all bushings /pads in all four spring buckets....and both u-joints in the jack shaft and a new gear on the tail of the transmission for my speedometer, for all parts and labor at my local Mack dealership for the total sum of $9200.00 and some change. The truck was down 3 days.

Sorry for the long post but I wanted to lay it all out for you so you would have a clear picture as to why these stands are, IMO a viable option..

[ranchhopper]

These new stands are designed for easier installation like you stated its a pain spreading the rear of the frame to slide the new one in.