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Discussion Starter #1 (Edited)
granetelli weight jacker arms review: (duw) NEW INFO/Q's 8/30/05

I decided to purchase some GMS arms off of ebay, there was a "Best offer" button where a buy it now would normally be, and I shot off a $150 offer, and suprisingly was accepted. I also had a $25 paypal coupon, so I basically ended up paying ~$135 for these arms shipped.

I know there's a lot of complaint about their service and the parts, but I am so far impressed. My only concern is the longevity of the poly bushings on the chassis side, Ive heard of people shearing them, but I don't have any threads to support that claim. They appear to be one piece bushings (I think), so I am going to measure the shells and see what I come up with.

The welds look good, not grounded off at all, but they look solid, and there's even an additional support plate at the poly side. On the spherical side, there is your typical spherical bearing, which has no play and feels very solid. I don't like how it screws in, but looks like you can get a bit of length adjustment with these arms. No bolts are included, but that's fine. Only part I am not sure about are the swaybar mounts.

Here's some pics:















They are by no means MM arms, but they look nice and I hope they hold up, another possible issue is the spring perch. It moves somewhat easily, and the perch is solidly mounted to the shaft, so I don't understand what part of the suspension moves when you adjust it.

I'll have driving impressions soon, I will be using these with stock upper arms, and eventually a panhard rod from MM. See you guys in a couple hours.
 

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When you adjust the spring perch (turning the threaded shaft with a bigass ratchet) you're raising or lowering the bottom mount for the coilspring, raising/lowering the top position of the spring and therefore the body of the car. The level of the LCA remains more or less the same (okay, yes, when the car's level changes there will be some adjustment in the position of the LCA since the chassis pivot point will change). What's not to understand?

It won't turn so easily when you get the weight of the car on it.
 

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Discussion Starter #3
I mean, I was curious whether or not the spring itself would rotate on the plate. It does, the poly isolators just stay in place and slide on it.

Install was horrible. Everything barely fit. there was no right/left markings on the arms, had to open the ears up on the axle LCA mounting points. The swaybar ended up being almost 2" too wide.

Took me 6 hours to install, and now the car vibrates hard when I get on it. I can't tell what it is, but it feels like its coming from the center console. I'm worried these arms are too short/too long, or installed opposite of how they should (left right orientation, of course). It could just be something I forgot to put back together, but everything looks ok. It feels like driveshaft rub, which doesn't make sense. These arms appeared to be the same length as the stockers, I laid on on top of a stocker to get an idea for the initial point for the spring perch height.
 

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I purchased these arms myself for my NortheastIron road race mustang. While they are not MM quality they work just fine. I didnt have much trouble installing them, I bought new bolts before the install which are SAE and had to drill the axle/frame holes out for the new bolts, but you reused the oem metric bolts they should bolt right in. You do have to unload the rear to adj the weight jackers, but once they are adj you dont have to mess with them. Yes the length is adj but thats a good feature in case your car is tweaked a bit you can string the susp to get the rear nice and square. The quality of these is ok. But hey for $200 you cant beat it if your a budget racer. I did not notice a huge difference over urethane lowers. They been on the car since the winter and have been thru 4 sprint racers so far. I cant complain. Al.
 

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Discussion Starter #5
302blown said:
I purchased these arms myself for my NortheastIron road race mustang. While they are not MM quality they work just fine. I didnt have much trouble installing them, I bought new bolts before the install which are SAE and had to drill the axle/frame holes out for the new bolts, but you reused the oem metric bolts they should bolt right in. You do have to unload the rear to adj the weight jackers, but once they are adj you dont have to mess with them. Yes the length is adj but thats a good feature in case your car is tweaked a bit you can string the susp to get the rear nice and square. The quality of these is ok. But hey for $200 you cant beat it if your a budget racer. I did not notice a huge difference over urethane lowers. They been on the car since the winter and have been thru 4 sprint racers so far. I cant complain. Al.
Were your arms marked left and right anywhere? Also, were you able to mount your rear swaybar?
 

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no the arms where not marked left or right. it doesnt matter I dont think. the poly bushings are 2 piece with a center pin, if the crack you can by them new from energy susp cheap, mine still seem to be fine, we'll see. funny, I dont use a rear swaybar so I cant comment on that.
 

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Discussion Starter #7
damn. I hope I can figure that vibration out. I'm so exhausted I have to get some sleep, but I dispatched an email to GMS about it, and maybe someone here might have some info. Looks purty though.
 

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Discussion Starter #8
Anyone have any thoughts? would a left/right swap cause this?
 

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Dont wait on a response from GMS. I sent several emails without reply and made several calls to which i could not speak to anyone other than an operator or salesperson. I have had nothing but problems with these arms. The bushings wear out within a week then your rear end will clunk. Your vibration is most likely due to a bad pinion angle or one side is adjusted differently than the other. I ordered a set of replacement bushings and within a week they were needing to be replaced. The quality of the spring perch also worries me. If you do not have a panhard bar your rearend will sway back and forth badly and cause bad handling and if the car is lowered much the tires will probably scrub the wheel well from all the movement. If i had the energy i would put my stock arms back on and throw these in the trash. Oh yeah i really had to squeeze my swaybar to get it in but i did get it in. I would NOT recomend anyone buying anything from gms, they put no engineering into there products, they rip off designs from other companies just look at there new k-member and aluminum RLCA's, also they have absolutely no customer support.
 

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Discussion Starter #10 (Edited)
dang, and you're local to me.

EDIT: How the heck did you get the bar to mount on the inside without snapping?
 

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Discussion Starter #12
hotrdlx said:
Hopefully youll have better luck with them than i have, but i really wish i had saved my money and bought a better set.
I hear ya.

I just can't believe you got that bar mounted. I think the arms would be fine if they had better bushings, however, I should get the measurements on them and see if MM ones will fit. I think it is a pinion problem, but I have no clue how to correct it. I'll be up GMS's butt about it the next couple of days, but they may end up on ebay should nothing work out.
 

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Discussion Starter #13
Its definately a pinion problem, I heard it loud and clear on the way home....driveshaft > ebrake bracket.

I guess the proper step would be to pull it all apart, swap the sides on the arms to see if they line up better, and measure the space between the new lca's and the stockers, and adjust out the heim joints to match (common sense, but when I set them over, they looked the same).

What a fvcking nightmare.
 

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I just put one side of the bar against the bracket then manhandled the otherside and pushed in on the sway bar until it flexed enough to fit into the other bracket. I have the gms replacement part # for the bushings and i have dimensioned drawings of the bushings for reference or cross reference to find another brand to fit, let me know if you need either.
 

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Oh and i have pics on my site of the bushings i took out after about 1,000miles, without a panhard bar the out side edges of the bushings ate themselves away within a few days due to the increased bind and you can see how they eggshaped and caused the rearend to clunk.
 

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Discussion Starter #16
hotrdlx said:
I just put one side of the bar against the bracket then manhandled the otherside and pushed in on the sway bar until it flexed enough to fit into the other bracket. I have the gms replacement part # for the bushings and i have dimensioned drawings of the bushings for reference or cross reference to find another brand to fit, let me know if you need either.

Both would be great.

So I take it you recommend I order a panhard bar this friday?
 

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I'd hock 'em and get some MM units--used, even. Heck, even the pro3i knockoffs can't be that bad--at least they have 3-pc bushings. Let some other poor schmuck deal with your GMS junk. :p
 

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While I aggree GMS products are mostly crap and they do just outright copy other products, if you know the problems associated with them you are a more informed buyer. I knew from the get go GMS had a bad name and the one problem I found with the GMS weight jacker arms is the bushings. It is a cheap old school hard durameter bushing that will split if the joint was twisted. With out a panhard bar your rear sways left and right and will eventually kill even a good urethane bushing. Energy susp makes a good replacement urethane bushing for the GMS arms that would be a wise investment. Best bet whether you have MM arms or GMS arms is to get a panhard bar if your blasting the turns. So far I have the GMS arms on my AI car with a panhard bar and I run up in the front of the pack most of the time. So my suggestion is to always research parts before you buy them. But yes GMS sucks and you'll never get a response from them.
 

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So back to your original problem, vibration.

Its most likely your pinion angle. With any adjustable part when you install it you have to check the adjustments, you cant just guesstimate. I suggest you park the car on a level area. Run a string down the left and right side of the tires to get the front tires pointing straight ahead. Then use a tape measure and measure the left wheel base and right wheels base. They should be the same, if not note the difference. Next put the rear tires on ramps. Go under the car with a T square or some other devise to measure the angle between the rear flange and driveshaft, the rear flange should be around 2-4 degrees down compared to the driveshaft. Now comes the fun part, disconnecting the lower arms at the chassis to adj the rod end length. You'll need to adj it to get the proper pinion angle and the same wheel base on both sides. When its all done and back on the ground you can double check it.
 

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hotrdlx said:
Dont wait on a response from GMS. I sent several emails without reply and made several calls to which i could not speak to anyone other than an operator or salesperson.
Not to rub it in, but that's just another reason some of us spend a little extra to go with Maximum Motorsports. Great products and great service before and after sales.
 
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