Flip Kit Questions, 73-87

[chevyrestoguy]

I just recently picked up an aborted '73 Cheyenne Super 1/2 ton shortbed fleetside project that the previous owner gave up on. He had installed a flip kit in the rear using the crappy AIM junk, and I noticed two things. The forward driveshaft yoke has 2.25" of gap (the machined area that slides into the trans) between the trans and the u-joint. It's way too much, and I was wondering if all flip kits will cause this condition? This truck was put together with parts from dozens of trucks, but I can almost swear that this driveshaft looks to to be the factory original to the truck. Do you think that maybe he put the flip cradles under the factory perches on backwards? I always figured that lowering the rear should send the driveshaft forward........

Do all flip kits need a shock relocator? It looks like there's no way to bolt up the shocks because the lower spring plate is right in line with the shock bolt.

[lolife99]

"forward driveshaft yoke has 2.25" of gap"

How long is the yoke? I usually like to have about and 1" of travel for the yoke. Take the driveshaft loose at the rearend and push it into the tranny tail shaft until it bottoms out. As long as you don't have too much or too little travel,... you should be fine. The hole in the "flip perch" should be towards the front of the truck. I would check that out also.

[N2TRUX]

Originally Posted by lolife99

".... The hole in the "flip perch" should be towards the front of the truck. I would check that out also.

That's the first thing that came to my mind as well. Check to see if they aren't put in wrong. That will pull the axle back further than required.

[lolife99]

Hmmm,... I got to thinking aout this,... and the flip perch (with the hole in the front of the bracket) "should" move the rearend towards the back of the truck. This helps keep the rearend centered in the wheel opening. (also keeps from having to cut the drive shaft). Pics would help alot.

[chevyrestoguy]

I checked it when I got home tonight, and the locating pin (the leaf spring pack bolt) is in the forward position. It's correct, so it appears that the driveshaft is the wrong one. The wheels are centered in the openings, too.

[lolife99]

"so it appears that the driveshaft is the wrong one"

What makes you say that?

[Big H]

One issue that has not been addressed is how the measurement is being taken. Are the wheels in the air with the suspension unloaded or is the truck on the ground under its own weight? Big difference...

As long as the spring plate is mounted with the center pin in the forward hole, then the flip bracket is in correctly no matter who's it is.

[chevyrestoguy]

The measurements were taken with jackstands under the rear axle, tires approx 1" off the ground. I'll take measurements with the truck on the ground, but I don't think it'll change anything.

"so it appears that the driveshaft is the wrong one"

I've got 2 5/8" inches of the slip portion of the yoke showing when the rear is on stands and the spring plates are correctly installed. The trans leaks out the yoke because it's not engaged enough, and it actually leaks worse when the truck is on it's wheels. This weekend, I'll bottom out the shaft in the trans and measure the difference. This truck was put together with parts from alot of different trucks, and I just have a sneaking suspicion that the driveshaft 'aint the original one. I hope I'm wrong, because that'll be one less thing to have to go buy.

I work 75 miles away, and when I get home, it's already dark. I hate daylight savings time.

[Big H]

If you have the stands under the axle then you are right, it will be the same measurement on the ground. As you stated, with the truck being a mish mash of parts you could very well have some incorrect driveline parts.

[LEEVON]

could have swapped trannys...the yoke could also be leaking from the weep hole. just plug it if it has one.

[chevyrestoguy]

Update: Pulled the driveshaft, and when I got it out from under the truck, I saw the yellow junkyard marking pen numbers on the tube. Yep, wrong driveshaft for the truck. Went to a buddy's shop and compared it to the original driveshaft from his '79 shortbed with a th350 and mine was .75" shorter. I need even more than that because the slip portion of the yoke is 4.0" and I was only engaged a little over an inch. I made a measurement of the exact size I need and am going "yarding" this weekend to find another one.

Also, put the helper leaf back under the spring pack, and was able to get the shock to bolt up. I'm just trying to get the truck in driveable condition, and will probably re-do the entire suspension with parts from Nathan in the future.