Front Suspension Fixes

[TMKHUM]

I've fixed a couple problems with the front suspension on my H2, and wanted to pass it along:

Problem 1: Snap or popping noise heard from front left of vehicle apparent during braking or turning.

Solution: There is a TSB on this which recommemds elongating the driver's side cross member holes and retightening bolts to 89 ft-lb.s. The real problem is too low of tension in the bolted connection. With the loading on the cross-member and 'low' bolt tension, the cross member shifts relative to the frame and pops. I know one of the hummer tech.s on the board suggested turning the bolts an additional 3/4 turn. This is along the right path, but will most likely yield the bolts which will prevent you from building addtional tension. The suggested fix is to go to higher strength bolts and a higher torque. The stock bolts are 10.9 quality with a max torque of 90 ft-lb.s. I have replaced these bolts with 12.9 quality (about 20% stronger) socket head cap screws which are torqued to 110 ft-lb.s This has eliminated the popping noise. (I went this route after the TSB didn't work)

BOLTS : 12 mm X 165 mm M12 12.9 bolts SHCS
Loctite medium strength
Re-use factory flange nuts
Use flat washer and locknut at the bolt head
Make sure all the corrosion coating is cleaned from threads and contact areas.

Problem 2: Brake dive

Solution: Well quite a few of us have cranked our front torsion bars for a bit more lift. When we have done this, the lower bumps stop does not or barely touches the lower a-arm. If you look at a proper z height setup, the lower arm is touching the bump stop.

Well, I read an article last week on the GM front suspension. It said the bump stop is actually part of the total spring rate (combined with torsion bar rate). It went onto say the bump stop also helps to minimize torsion bar fatigue. I fabbed a pair of spacers that dropped the bump stop a 1/2". After doing this, brake dive has decreased considerably. I was actually surprised how effective this was. The proper way is to mold a longer a bump stop, but the spacer works.

Hope this helps. The usual: use at your own risk.

[TMKHUM]

I've fixed a couple problems with the front suspension on my H2, and wanted to pass it along:

Problem 1: Snap or popping noise heard from front left of vehicle apparent during braking or turning.

Solution: There is a TSB on this which recommemds elongating the driver's side cross member holes and retightening bolts to 89 ft-lb.s. The real problem is too low of tension in the bolted connection. With the loading on the cross-member and 'low' bolt tension, the cross member shifts relative to the frame and pops. I know one of the hummer tech.s on the board suggested turning the bolts an additional 3/4 turn. This is along the right path, but will most likely yield the bolts which will prevent you from building addtional tension. The suggested fix is to go to higher strength bolts and a higher torque. The stock bolts are 10.9 quality with a max torque of 90 ft-lb.s. I have replaced these bolts with 12.9 quality (about 20% stronger) socket head cap screws which are torqued to 110 ft-lb.s This has eliminated the popping noise. (I went this route after the TSB didn't work)

BOLTS : 12 mm X 165 mm M12 12.9 bolts SHCS
Loctite medium strength
Re-use factory flange nuts
Use flat washer and locknut at the bolt head
Make sure all the corrosion coating is cleaned from threads and contact areas.

Problem 2: Brake dive

Solution: Well quite a few of us have cranked our front torsion bars for a bit more lift. When we have done this, the lower bumps stop does not or barely touches the lower a-arm. If you look at a proper z height setup, the lower arm is touching the bump stop.

Well, I read an article last week on the GM front suspension. It said the bump stop is actually part of the total spring rate (combined with torsion bar rate). It went onto say the bump stop also helps to minimize torsion bar fatigue. I fabbed a pair of spacers that dropped the bump stop a 1/2". After doing this, brake dive has decreased considerably. I was actually surprised how effective this was. The proper way is to mold a longer a bump stop, but the spacer works.

Hope this helps. The usual: use at your own risk.

[TMKHUM]

I've fixed a couple problems with the front suspension on my H2, and wanted to pass it along:

Problem 1: Snap or popping noise heard from front left of vehicle apparent during braking or turning.

Solution: There is a TSB on this which recommemds elongating the driver's side cross member holes and retightening bolts to 89 ft-lb.s. The real problem is too low of tension in the bolted connection. With the loading on the cross-member and 'low' bolt tension, the cross member shifts relative to the frame and pops. I know one of the hummer tech.s on the board suggested turning the bolts an additional 3/4 turn. This is along the right path, but will most likely yield the bolts which will prevent you from building addtional tension. The suggested fix is to go to higher strength bolts and a higher torque. The stock bolts are 10.9 quality with a max torque of 90 ft-lb.s. I have replaced these bolts with 12.9 quality (about 20% stronger) socket head cap screws which are torqued to 110 ft-lb.s This has eliminated the popping noise. (I went this route after the TSB didn't work)

BOLTS : 12 mm X 165 mm M12 12.9 bolts SHCS
Loctite medium strength
Re-use factory flange nuts
Use flat washer and locknut at the bolt head
Make sure all the corrosion coating is cleaned from threads and contact areas.

Problem 2: Brake dive

Solution: Well quite a few of us have cranked our front torsion bars for a bit more lift. When we have done this, the lower bumps stop does not or barely touches the lower a-arm. If you look at a proper z height setup, the lower arm is touching the bump stop.

Well, I read an article last week on the GM front suspension. It said the bump stop is actually part of the total spring rate (combined with torsion bar rate). It went onto say the bump stop also helps to minimize torsion bar fatigue. I fabbed a pair of spacers that dropped the bump stop a 1/2". After doing this, brake dive has decreased considerably. I was actually surprised how effective this was. The proper way is to mold a longer a bump stop, but the spacer works.

Hope this helps. The usual: use at your own risk.

[RIC-H0]

What did you end up making the bump stop spacer out of, and what are the dimensions, so I can pre-make mine before I actually take them out!

Thanks,
Ric-H2

[alecs wife]

Thanks for the advise. I fixed mine this morning. The bolts were very loose!!!!

[TMKHUM]

Bump stop info:

The bump stop has a steel backplate with a single threaded stud and locating tab. It takes about 5 minutes to remove the bump stop.

Ok, I fabbed mine from 2" wide piece of bar stock, 1/2" thick. The 1/2" is probably a little too thick, as you don't completely engage all the threads on the mounting nut...you may want to go 3/8" thick. You'll have to drill two holes for the stud and locating tab.

Now I didn't put a tab on the bar stock spacer, but so far everything has stayed aligned.

To install it, simply jack under the frame until the bump stop clears.

[RIC-H0]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by PhilD:
Ric, did you ever try those +2 keys? <HR></BLOCKQUOTE>
No Phil, I never have, I'm still waiting to have all the front end work done prior to messing with them(Warranty reasons!) If and whenever I do not have any steering or suspension problems, then I'll go ahead and do it! Seems as if I am always at the dealership, and when it's related to the front end, that's the 1st question that is asked "Have you adjusted your torsion bars any?"

Ric-H2

[AZhummer]

I just looked at my Z height and sure enough the space between the bumper and the lower arm is atleast 1/2 inch. I will fab some spacers as well. Aluminum stock ok?

[TMKHUM]

Yes, aluminum should work also!

[DavidAragon]

... very interesting. Where was the article? On the web? I'd be interested in reading it.
Thanks,
David

[TMKHUM]

try oramagazine.com

The november issue covers a 5" lift for a GM truck. It has a picture of the bump stop spacers superlift uses on there lift kit.

Tom