 
     |
| Cross member bump stop tower shortening recommendations with lowered front suspension (Page 1/1) |
|
gtoformula
|
APR 27, 09:45 PM
|
|
Hi guys. I don't often create posts soliciting for recommendations but hoping that some of the gurus out there can provide some assistance.
For starters my very specs are: 1986 GT, 3800SC, 5 spd Getrag, Koni front shocks, rear coilovers with Monroe gas struts, rear anti swap bar (front sway bar from another '86 GT+).
Issue: the car has two issues,
1) the front end really "crashes" on large bumps.
2) when hitting small, sharp bumps there is a rattle that seems to transmit up to the steering wheel.
Issue 1): The front springs had been cut prior to my purchasing the car and I was told that only 1/2 coil was cut off. I"ll see if I can post a pic. BTW, running P235/45R17s. I have not done an actual measurement, but there is not much clearance between the bumper stops and the lower control (probably 1/2" or less). I've searched and found a couple of write ups on this subject and found that either 3/4" to 1" is the recommended amount to cut out of the bumper towers. I'd only like to take apart the front suspension to do this job once. Don't want to take off not enough, or worse, too much. Suggestions on how much I should cut/reweld or, even better, the stock factory dimension for the dimension between the bump stop and lower control arm.
https://www.fiero.nl/forum/Forum2/HTML/138754.html
https://www.fiero.nl/forum/Forum2/HTML/125475.html
Issue 2): So are I've swapped out parts with another car ... steering rack, intermediate shaft, steering column. I've also pulled apart the steering columns and tightened the three tilt steering pivot bolts. None of this seemed to be making much of a difference. I also just ordered/received a 1" Monroe steering damper hoping that this could provide some bump rattle that I am experiencing. I've yet to install this part, but just had an eye operation so can't work on that for a few days. This rattle is now so annoying that I've decided to hold off upgrading the seats or other "fun" stuff until these issues are resolved.
Really hoping for some magical recommendations from the forum group to help me past these issues.
|
|
|
|
cvxjet
|
APR 28, 12:04 AM
|
|
|
|
|
Patrick
|
APR 28, 02:21 AM
|
|
| quote | Originally posted by gtoformula:
I've searched and found a couple of write ups on this subject and found that either 3/4" to 1" is the recommended amount to cut out of the bumper towers. I'd only like to take apart the front suspension to do this job once. Don't want to take off not enough, or worse, too much. Suggestions on how much I should cut/reweld or, even better, the stock factory dimension for the dimension between the bump stop and lower control arm.
|
|
If you don't wish to trust that 3/4" is the ideal width of "cone" to remove, then you'll have to check for yourself. Remove your front springs, temporarily remove the rubber bump stop, reassemble everything without springs (and rubber bump stop), and measure (at the end of the metal cone) how far extra you can move the lower control arm up before your shocks bottom out.
|
|
|
|
gtoformula
|
APR 28, 09:43 AM
|
|
cvxjet and Patrick. Thanks for your input and advice. I like the idea cvxjet had regarding using hose clamps to provide a straight cutting line for the crossmember bump tube cutting lines. Will be using that. I also like the idea that Patrick had to remove the spring and be able to measure the suspension travel to ensure that I don't cut off enough tube to allow the shocks to bottom. Both great ideas guys and I look forward to tackling this project just as soon as my recent eiye cataract surgery has healed. I have hopes that the suspension bottoming out may have had something to do with the rattle that I get in the steering wheel or perhaps the steering dampener will help. I'll update this post when I've had some success with that issue.
Thanks again guys!
|
|
|
|
zkhennings
|
APR 28, 11:28 AM
|
|
I cut out probably an inch of mine, I never had issues with the tire hitting the fender or bottoming out the shock. Just goes to show it depends what wheels, tires, shocks, and springs you are running. I would do what Patrick said and after pulling the spring out, cutting the cone a little higher up so that the weld will not end up too close to the rubber stop itself. Then with the bumpstop removed before re-welding, you can measure travel until either shock bottoms out or tire hits fender, cut off the amount needed from the part you just cut off the cone, and then get it welded back together.
For example, make cut in cone 3" above rubber stop. Reassemble control arms, spindle, shock, and wheel. Cycle through travel and see if shock bottoms or tire touches. Measure how long bumpstop needs to be and remove the correct amount from the part you cut off. Weld. Pics of mine.
I cut mine too close to the rubber stop and got a little burning rubber action as a result during welding.
|
|
|
Patrick
|
APR 28, 03:19 PM
|
|
One thing I might add is to keep in mind that the rubber bump stop will squish down pretty flat if/when the lower control arm hits it during normal operation, so don't include the height of the rubber bump stop when making your calculations for the cut-down height of the metal tower/cone.
|
|
|
|
gtoformula
|
JUN 06, 09:13 PM
|
|
| quote | Originally posted by cvxjet:
I cut my bump-stop "towers" by 3/4"...But then the tire was hitting the fender at full compression. Luckily, I had converted the rubber pieces to a screw-on setup....So I just added a 1/8" washer and that (basically) solved the problem.
Here are some pics of what I did; I used a hose clamp to get the proper line, then carefully cut the section out and took it to a friend to weld it back together. He also welded a nut at the hole where the rubber would usually be inserted. I cut off the nub and drilled a hole and use a 1/4" stainless bolt and washer to hold them on now.
For the last 20+ years I have had a rattle in the steering column- I think it is (Basically) part of the design- but I am interested in any suggestion that may be posted here...
|
|
I may have solved the steering column rattle on bumps issue. There seemed to be some side to side play in the wheel, but the bearings were new. I think that the bearing shell had been pulled down into the steering column housing instead of flush with the casting. I used a thin washer inside the turn signal cancellling cam (by the shaft spring) to keep the bearing inner race fully seated in the bearing. This seems to have made a big improvement with the rattle issue. The washer needs to be 1" OD (to fit in the turn signal cancellling cam) and 3/4" ID (to fit over the column shaft). I made mine from a steel washer, but a cut down nylon washer would also probably work. Just need to pull the steering wheel, depress the steering shaft lock, place the washer under the turn signal cancelling cam and reassemble. A bit of work, but much easier than pulling everything apart to work on the bearings.
|
|
|
|
pmbrunelle
|
JUL 23, 06:38 PM
|
|
When trimming front bumpstops, is a 0.1" tall weld bead OK, or is there a risk of the weld rubbing on the spring?
Do I need to grind these weld beads flatter?
|
|
|
|