33 street rod rear suspension hang

[easyrider]

I have the Factory Five 33 street rod, no fenders, Blueprint SBC 383 with the TKX transmission. I got with the kit the 8.8 Moser rear end with the 4 link suspension. My wheels have not arrived yet so the chassis is suspended on a lift. My question is this-the rear end hangs low, if I raise it up and hookup my drive shaft it bottoms out on the tunnel and I dont want that weight/load put on the driveshaft. Is this normal or right? I have double checked the shocks and the way they are mounted and everything appears to match up with the manual but it just does not seem right. The problem goes away when the car is sitting on wheels and tires but what if I have to jack the car up for some reason, the drive shaft will bottom out on the tunnel/floorpan!! Am I missing something?

[NAZ]

Define "bottom out" in relation to the axle travel. Do you mean the driveshaft contacts the tunnel when the shocks are it full compression?

The driveshaft should never be able to contact anything on the chassis at any point along the full travel of the suspension. If it does, you are setting yourself up for a damaged driveline at minimum, and catastrophic failure with some major damage and possible injury at the upper end of this potential for failure.

Have you set the pinion angle yet? Harder to do without wheels and tires but certainly doable if you know the actual diameter of the tires you plan to run. If the pinion angle is not set it's too early to assess driveshaft clearance.

[sread]

I think OP is referring to the driveshaft making contact at full droop. I'm pretty sure it occurs on most builds although it depends on which shocks being used, ride height, pinion angle, etc. I added limit straps as have others because I wasn't comfortable with it either.

[cob427sc]

I believe what the problem is, when the axle hangs free the driveshaft actually contacts the aluminum pan that extends across under the driveshaft, just beyond (several inches) the transmission. I actually trimmed back part of this pan to allow for more axle movement but still ended up adding axle limit straps to prevent this from interfering. There is very little distance that the axle can drop in an unweighted situation before the driveshaft will rub on the aluminum.

[FF33rod]

This has been noted before in some of the other build threads, seems to depend on the engine, transmission, rear combo and (if I'm not mistaken) seems to be happening more on gen 2. In any case, what most have done is add travel limit straps. Might want to look up PeterH build thread or DM him https://thefactoryfiveforum.com/show...3-Hot-Rod-1134

Steve

[BC Huselton]

This has been noted before in some of the other build threads, seems to depend on the engine, transmission, rear combo and (if I'm not mistaken) seems to be happening more on gen 2. In any case, what most have done is add travel limit straps. Might want to look up PeterH build thread or DM him https://thefactoryfiveforum.com/show...3-Hot-Rod-1134

Steve

Options: Mine is a Gen II with Automatic Trans and I did not want to hit anything any time. Got 4" pipe, cut it in half and added side flanges to mate / weld into the FFR cross bar after I cut it out and structure the safety loop to be bolted in. Plenty of clearance, no issues with structural integrity and no worry about hitting. See Pics.

Shaft Drop Solution.jpg

[33fromSD]

I added travel limit straps to my Gen2 chassis, I too am running the moser 8.8 rear with 4-link. With the travel limit straps installed, when I jack up the rear by the frame and let the suspension hang, the closest my drive shaft comes to hitting floor pan is 1/4"

Jim

[easyrider]

Yes this is exactly what I am referring to. I am prepared to go the limit strap route, no problem with that, just wanted to make sure I wasnt missing something. Thank you for the input.

[RoadRacer]

Is it because I have a 3 link, but I don’t see my driveshaft close to anything on full droop? With shocks attached though so not full-full droop And gen1.

[easyrider]

Sounds like limit straps are the answer. I can do that. Thanks for the feedback. Moving forward again.

[NAZ]

Sounds like limit straps are the answer. I can do that. Thanks for the feedback. Moving forward again.

Limit straps work well to limit shock travel and are very common in off-road racing to help prevent shock damage. Now, they don't necessarily have to be placed at or near the shocks to prevent the driveshaft from contacting the chassis at full droop. There is an advantage in placing a limit strap on the axle near the longitudinal center line of the pinion. This allows lateral rotation of the axle, and therefore, more wheel travel. Just something to consider.

[edwardb]

My truck build with similar parts (3-link, Moser axle, etc.) did the same thing. When I posted about it in my build thread, another builder suggested mounting the shocks in the upper frame mounting holes. The ones that are normally used for a lower overall ride height, e.g. track use, whatever. That was just enough to keep the driveshaft off the frame at full droop. If your 33 hot rod has those same holes, maybe that would work for you. I believe the truck and the hot rod use the same shocks.

[peterh226]

Welcome to the fun Easyrider. Steve gave you the link to what I did with my 3-Link. The rear suspension has been a challenge to get OK. The upper adjustment link was the other problem as it was not long enough to permit the need adjustment and once the read is rotated around, the link hit the trunk sheetmetal. Having some fun now trying to get the correct ride height with the fenders so there is no contact. Lots of moving parts with adjustment and many holes to choose from.

[easyrider]

shockclear3.JPGshockclear2.JPGshockclear1.JPGadjuppercontrol.JPG
I have an update. I needed to dump the upper control arms and go to adjustable upper control arms to get my pinion angle correct. This improved the clearance on the driveshaft by a lot. I did have to cut out a section by the coil overs for clearance and I did have to keep the limit straps. I also made a spacer for under the rear of the transmission, this is probably optional, most of the clearance was achieved with the rear pinion angle being corrected. I hope the attached pictures show this for anyone having the same problem. Really appreciate the input from everyone. I am getting closer!