New bolts needed for UPR control arms?

[FiveLeeter]

Bought a set of UPR control arms a few weeks back and got them installed last weekend (13 days ago). Ever since, the car has experienced a clunk when going over big bumps. Smooth roads it's fine, but big bumps it sounds horrible.

Tried several things, from zip tying the brake lines to the control arm, cutting the bump stops (I also lowered the car at the same time), and neither worked.

Friday, a friend of mine and I took a drive down a known bumpy road to see if he could figure it out. Was definitely predominate from the rear driver side. Parked the car, I laid under it while he rocked the car front to back. Found that the axle side of the lower control arm is shifting about 1.5mm from front to back.

We got back home and jacked up the car, took the wheel off, and removed the LCA bolt. Found that the oem bolt is a stepped design from 14mm down to ~12.5mm, however the steel tool pin that UPR uses is a 14mm full diameter ID. This is causing the control arm to almost torque when on a bump.

Anyone else ever had this problem? Trying to source a replacement bolt, but it's harder than I expected to find out exactly like the OEM bolt but without the step.

 

[Brezick]

Mine have always been clunky, but i attributed that to the fact I got the solid spherical bushing. I should go check the bolts.

 

[Napoleon85]

I re-used the stock bolts and have never had a clunk. Did you put the bolt back in the same way it came out? I have a spherical UCA and it doesn't clunk either, but it does make creaking/groaning noises as it's being articulated.

 

[FiveLeeter]

it's the poly side having the issue, the spherical is fine.

 

[Godzirra]

I have the spherical one with the mount and mine doesn't clunk

 

[FiveLeeter]

Lower Control Arms not upper.

 

[Norm Peterson]

I'll bet $ that you took the LCAs out of the box and just slapped them on the car without paying any attention . . . short of having an arm with an obviously wrong bushing or metal inner sleeve there is this one other thing to look for . . .


Norm

 

[FiveLeeter]

what are you referring to Norm?

I took them out of the box and measured them in accordance with the stock ones. Put a bolt through the stock control arm, put the poly end on the bolt, and turned the adjuster nut until the spherical end fit on the bolt as well. Then I tightened the nuts down and installed on the car with the longer portions facing the inside of the car the same way stock is.

Length of the control arm would not cause the torquing motion that I am experiencing. Having extra space between the tool pin and the bolt WOULD.

 

[Norm Peterson]

Did you happen to compare the lengths of the poly bushings and the metal inner sleeves?


Norm

 

[Sky Render]

Also, the rear bushings are supposed to be offset to one side. Maybe you put them on backwards?

 

[FiveLeeter]

overall length was the same, but like I said the new one is a 14mm tool pin instead of the stepped design that the original was.

Also, the rear bushings are supposed to be offset to one side. Maybe you put them on backwards?

Install guide said to put the longer side toward the pumpkin.

 

[Norm Peterson]

If you've got a solid stack of metal from one LCA bracket "side" all the way through and out the other, the actual bolt diameter does not matter as long as you can torque it sufficiently. The bolt does not hold the joint together in "direct shear" of its own shank.

Bushing/arm orientation should not matter at all as far as joint tightness is concerned. Geometrically, there is a slight difference.


Norm

 

[FiveLeeter]

then what you do hypothesize is my issue? laying under the car with the car rocking front to back, you can see the control arm physically move ~1.5mm (guessing) separate of the axle housing.

 

[BMR Tech]

Most companies use a straight 14mm sleeve, including us.

Are you torquing the bolts to 129-130ftlbs?

Also, 1.5mm of movement may not be a bad thing, depending on the durometer of the LCA Bushing(s). Like Norm stated, if the bolt is TQ'd properly, the bolts should not play as large a factor as one may think, in terms of LCA movement (front-back) within the chassis, but it really just depends. If the car is simply sitting, parked, and you can move the arm, something does not seem right.

If you feel confident that it is a bolt diameter issue, take the bolt and wrap it with something and test it. (wrap the 12.5mm portion until the diameter becomes closer to 14mm)

 

[Norm Peterson]

then what you do hypothesize is my issue? laying under the car with the car rocking front to back, you can see the control arm physically move ~1.5mm (guessing) separate of the axle housing.

More than hypothesis at this point.

Your "bolted joint" goes bolt head/bracket side/poly/other bracket side/nut, with the inner sleeve doing little more than keeping the hole in the poly round. It's supposed to go bolt head/bracket side/inner sleeve/other bracket side/nut, though I don't think any of the mfrs of poly-bushed control arms ever tell people that.

Remember that lube that you smeared on the poly faces? That's where you're getting the easy motion from, and you're sliding the joint until everything does come up hard against the bolt . . . that 1.5mm (give/take) is consistent with the dimensions given.

This kind of joint is supposed to maintain its position by steel-on-steel friction, developed from clamp load through the stack of pieces being clamped (just like you'd clamp three pieces of wood together to hold them in the same relative positions). Wasting every bit of torque trying to compress the poly is obviously getting you nowhere, because as soon as the poly slips (rotationally) due to suspension movement over bumps it is entirely free to slide fore/aft and clunk.


Norm

 

[FiveLeeter]

I originally torqued the bolts to 129 ft-lbs, but Jeremy stressed to me that that was too much for Energy Suspension bushings and now to go past 80 ft-lbs. The problem has persisted through both torque values.

The bolt is the only common factory between this. I bought some Grade 10.9 bolts the same dimensions as the oem minus the step down 14mm the entire way. going see if this remedies the issue, otherwise the stockers are going back on. Just tired of chasing headaches.

 

[FiveLeeter]

More than hypothesis at this point.

Your "bolted joint" goes bolt head/bracket side/poly/other bracket side/nut, with the inner sleeve doing little more than keeping the hole in the poly round. It's supposed to go bolt head/bracket side/inner sleeve/other bracket side/nut, though I don't think any of the mfrs of poly-bushed control arms ever tell people that.

Remember that lube that you smeared on the poly faces? That's where you're getting the easy motion from, and you're sliding the joint until everything does come up hard against the bolt . . . that 1.5mm (give/take) is consistent with the dimensions given.

This kind of joint is supposed to maintain its position by steel-on-steel friction, developed from clamp load through the stack of pieces being clamped (just like you'd clamp three pieces of wood together to hold them in the same relative positions). Wasting every bit of torque trying to compress the poly is obviously getting you nowhere, because as soon as the poly slips (rotationally) due to suspension movement over bumps it is entirely free to slide fore/aft and clunk.


Norm

so what is your suggestion to remedy this issue?

 

[Norm Peterson]

Drop the D.S. joint that's "moving".

Measure the length of the inner sleeve.

Measure the length through the poly bushing.

Post what you find.


Norm

 

[FiveLeeter]

will do. Going to double check the center to center while I have it off just to be absolutely sure it didn't shift anywhere.

 

[FiveLeeter]

Reporting back. Center to center was perfect when I verified it again with oem LCAs and hardware. Swapped in the 14mm fasteners and the noise from the poly went away completely. The clunk turned into a tink, so I bought additional fasteners for the spherical side. I'll swap them out tomorrow.

For the measurements you requested, the poly is 2.429" but couldn't measure the tool pin. It definitely feels slightly sunk in from the poly though.