Front Weight Jacks- Bolt up or down?
#1
Front Weight Jacks- Bolt up or down?
I'm thinking about building some front weight jacks and am debating if I want to put the bolt going up through the "frame" rail and into the engine compartment or down like the few sets of commercial ones out there are setup.
I figure:
I figure:
- up is easier to adjust but could get in the way of stuff in the engine bay and requires drilling a big stinking hole through the frame rails
- down is easier to do and less obtrusive but a MUCH bigger hassle to adjust (I'm guessing that it pretty much means having to get it in the air to adjust it, but I'm not sure that you can really adjust them well with the car's weight on them either way).
#2
COTM Editor
iTrader: (22)
Join Date: Mar 2001
Posts: 9,909
Likes: 0
Received 1,857 Likes
on
1,272 Posts
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Front Weight Jacks- Bolt up or down?
Yes, weight has to be removed to screw the jacks. The acme threads are designed to not slip with weight on it.
The following users liked this post:
91banditt2 (11-11-2020)
#3
Moderator
iTrader: (3)
Re: Front Weight Jacks- Bolt up or down?
Agreed....gotta take weight off. ....I only adjusted mine a few times, but you don't need to have the tire off the ground, just take the majority of the weight off. I used the effort required to turn the bolt as a gauge as to how much stress was on the jack. It was pretty easy to do.
#4
Supreme Member
iTrader: (11)
Join Date: Sep 1999
Location: NJ
Posts: 4,345
Received 298 Likes
on
234 Posts
Car: 92 Firebird
Engine: 4.8 LR4
Transmission: T56
Axle/Gears: 3.45 9 Bolt
Re: Front Weight Jacks- Bolt up or down?
//<86TA>\\ did the screw up through the frame rail, and I plan to also, I don't remember him talking about taking the weight off the front when adjusting them
#5
#6
Supreme Member
iTrader: (14)
Join Date: Aug 2006
Location: Central NJ
Posts: 12,651
Likes: 0
Received 45 Likes
on
43 Posts
Car: 86 Trans Am, 92 Firebird
Engine: 408 sbc, 3.1L of raw power
Transmission: TKO600, T5
Axle/Gears: Moser 9", 3:70 trutac, 3:23 torsion
Re: Front Weight Jacks- Bolt up or down?
I installed the bolt up, front and rear. If you take the time to align the holes when you drill them, no real strength is lost and the hole is a reasonable size. I made a drill guide using a jack bolt which I drilled a pilot hole through the center.
#7
Re: Front Weight Jacks- Bolt up or down?
I need to get a better look at what you end up with but I'm debating a bushing made to fit the UMI K-member spring pocket to use as a drilling guide, but right now it's sort of a half-formed idea without any measuring or a good picture of what I'm doing.
Trending Topics
#8
Supreme Member
iTrader: (4)
Join Date: Sep 2010
Location: Double Bratville
Posts: 1,617
Likes: 0
Received 42 Likes
on
31 Posts
Car: '89 Formula
Engine: LS2
Transmission: 4L65E
Axle/Gears: MW 3.42 12 Bolt
Re: Front Weight Jacks- Bolt up or down?
Of course, I used the stock k-member. Cut a hole around the "rind" - where the spring sat. Drilled a pilot hole. Then increment cut that "rind" and hammered flat for plate to sit flush. Increment cutting helped for welding penetration. Then used a hole saw (was very easy, actually), then used another similar bolt to hold the plate in place for welding upside down on the garage floor (my father did that - thanks Dad). Used some spacers to make sure there was free space maintained between the frame rail and the plate being welded.
The following users liked this post:
Jaysz28 (11-13-2020)
#10
Supreme Member
iTrader: (14)
Join Date: Aug 2006
Location: Central NJ
Posts: 12,651
Likes: 0
Received 45 Likes
on
43 Posts
Car: 86 Trans Am, 92 Firebird
Engine: 408 sbc, 3.1L of raw power
Transmission: TKO600, T5
Axle/Gears: Moser 9", 3:70 trutac, 3:23 torsion
Re: Front Weight Jacks- Bolt up or down?
Can you give more information about what you did? Pictures/video of the process or results? What diameter hole did you cut and how did you mount your "nut?"
I need to get a better look at what you end up with but I'm debating a bushing made to fit the UMI K-member spring pocket to use as a drilling guide, but right now it's sort of a half-formed idea without any measuring or a good picture of what I'm doing.
I need to get a better look at what you end up with but I'm debating a bushing made to fit the UMI K-member spring pocket to use as a drilling guide, but right now it's sort of a half-formed idea without any measuring or a good picture of what I'm doing.
#11
Supreme Member
iTrader: (14)
Join Date: Aug 2006
Location: Central NJ
Posts: 12,651
Likes: 0
Received 45 Likes
on
43 Posts
Car: 86 Trans Am, 92 Firebird
Engine: 408 sbc, 3.1L of raw power
Transmission: TKO600, T5
Axle/Gears: Moser 9", 3:70 trutac, 3:23 torsion
Re: Front Weight Jacks- Bolt up or down?
For the stock K member I cut out to top of the spring pocket and welded in the nut and plate. This was done with the k member removed from the car. Then I put it back in place and marked the hole on the frame through the nut. Removed the k member and drilled the bottom of the frame rail, i believe it was a 1.25" hole as the jack bolt is 1.125. Then I put the k member back in place, and threaded the jack bolt that I had previously drilled a 1/4 pilot hole all the way through up through the nut and into the frame rail until it hit the other side. Then using a long 1/4" bit i drilled through the top of the frame rail. I finished the hole from the topside with the 1.25" hole saw and I was finished. The holes were perfectly aligned without being excessively large.
This was back in 2010 I think, not sure I have pictures and the car was sold a couple years back.
This was back in 2010 I think, not sure I have pictures and the car was sold a couple years back.
#12
Re: Front Weight Jacks- Bolt up or down?
Of course, I used the stock k-member. Cut a hole around the "rind" - where the spring sat. Drilled a pilot hole. Then increment cut that "rind" and hammered flat for plate to sit flush. Increment cutting helped for welding penetration. Then used a hole saw (was very easy, actually), then used another similar bolt to hold the plate in place for welding upside down on the garage floor (my father did that - thanks Dad). Used some spacers to make sure there was free space maintained between the frame rail and the plate being welded.
Edit: Brian, as much as we've talked on here I've never seen your build thread. It looks like some of what I was wondering about is in there, I'll try to get through it later tonight.
Last edited by 83 Crossfire TA; 11-17-2020 at 06:02 PM.
#14
Supreme Member
iTrader: (4)
Join Date: Sep 2010
Location: Double Bratville
Posts: 1,617
Likes: 0
Received 42 Likes
on
31 Posts
Car: '89 Formula
Engine: LS2
Transmission: 4L65E
Axle/Gears: MW 3.42 12 Bolt
Re: Front Weight Jacks- Bolt up or down?
A decent amount of adjustment on the front. The back is what is limited.
I swapped out the springs to Hypercoil 11" from these Eibach 9.5" when I added .5" ext BJ's. And sent the drop spindles back for upgrade to beefier RR version. Hole saw is upper left. Bump stops I trimmed down. You can see I also used Spohn's strengthening plate for their coilovers - thought it was a good idea regardless.
I swapped out the springs to Hypercoil 11" from these Eibach 9.5" when I added .5" ext BJ's. And sent the drop spindles back for upgrade to beefier RR version. Hole saw is upper left. Bump stops I trimmed down. You can see I also used Spohn's strengthening plate for their coilovers - thought it was a good idea regardless.
#15
Supreme Member
iTrader: (4)
Join Date: Sep 2010
Location: Double Bratville
Posts: 1,617
Likes: 0
Received 42 Likes
on
31 Posts
Car: '89 Formula
Engine: LS2
Transmission: 4L65E
Axle/Gears: MW 3.42 12 Bolt
Re: Front Weight Jacks- Bolt up or down?
Suspension Rebuild: https://www.thirdgen.org/forums/susp...g-vetruck.html
I believe this is what I used: https://www.speedwaymotors.com/AFCO-...bly,23487.html
I believe this is what I used: https://www.speedwaymotors.com/AFCO-...bly,23487.html
#16
#17
Re: Front Weight Jacks- Bolt up or down?
Suspension Rebuild: https://www.thirdgen.org/forums/susp...g-vetruck.html
Am I reading correctly that you're using both drop spindles and extended ball joints???
I believe this is what I used: https://www.speedwaymotors.com/AFCO-...bly,23487.html
#18
Supreme Member
iTrader: (4)
Join Date: Sep 2010
Location: Double Bratville
Posts: 1,617
Likes: 0
Received 42 Likes
on
31 Posts
Car: '89 Formula
Engine: LS2
Transmission: 4L65E
Axle/Gears: MW 3.42 12 Bolt
Re: Front Weight Jacks- Bolt up or down?
Yes, you could easily swap swivel to non-swivel.
Yes, 2" DS with .5" ext BJ and 11" spring - when I added the BJ's it necessitated the longer spring. I believe this is about as much as we can go without ruining the a-arm angles. With just the DS, I could pull out the spring with fingers when I fully screwed the bolt all the way up (swivel cup fully recessed up in the pocket).
Hyperco (they also have 9.5")
I have the 18Z0900-11
Yes, 2" DS with .5" ext BJ and 11" spring - when I added the BJ's it necessitated the longer spring. I believe this is about as much as we can go without ruining the a-arm angles. With just the DS, I could pull out the spring with fingers when I fully screwed the bolt all the way up (swivel cup fully recessed up in the pocket).
Hyperco (they also have 9.5")
I have the 18Z0900-11
Thread
Thread Starter
Forum
Replies
Last Post