VIN K UIM Problem

[Vitaminmopar]

OK, my wife's LeSabre is down for a few more days while I wait for a replacement UIM from ineedparts.com (this is APN manifold). I replaced the valve cover gaskets, lower intake gaskets and installed a new APN UIM. All went well until I tried to torque the UIM. I had a difficult time getting the UIM bolts to reach torque specification. In fact I lost count of how many times I went through the bolt torque sequence. I would get the bolts to reach spec then on recheck find the bolts below spec and need to be tightned a little more. As it was O dark 30 and I was beat, I quit working on the LeSabre after I got all the bolts to reach spec and stable. In the light of the next day I found a crack beneath one of the long bolts located aft of the throttle body and at one bolt on the passenger side of the UIM. The other long bolt aft of the the throttle body was sunken. It appears the bolts were being drawn throught the UIM. The remaining bolt points look normal but I wonder. My first thought was that I set the torque wrench wrong. I checked my torque wrench and it was set at 89 inch pounds. I was using a Proto click stop inch pound torque wrench and torqued using 4 steps 25,50,75 and 89 inch pounds. So on to the next step which was to phone ineedparts.com.
I spoke with Thomas (TOM) at ineedparts.com and they warranteed the UIM. He stated that they had replaced some UIM due to the bolts being drawn through them. He suggested I call Graywerks and confirm the torque specs as being correct, so I did. Spoke with Jim Strong, Tech Support Manager and he confirmed the torque specs were 89 inch pounds same as factory and was unaware of any isses with the bolts being drawn through the UIM. I checked operation of the torque wrench by redoing the front valve over bolts and throttle body bolts, no problems there. So how do I avoid this problem with the second UIM? Have others on this forum experianced what I did in replacing the UIM.
One final thing, bolts were installed dry, no oil or thread locker.

[CoastieWight86]

Sorry man, I cant say I have had that issue. I just did mine the other day. I did notice that a few bolts seemed to be under torqued when I got through all of them but after another pass with the wrench all was good. Hopefully it was just a defective UIM that you got and not a bad torque wrench.

[00Beast]

I'd use blue thread locker on them. Steel bolts in an aluminum manifold = Asking for trouble with no locker. I'd also chase all the threads with the proper thread chaser to ensure an accurate torque. A good set of Craftsman thread chasers is $50 at sears and includes Metric, Standard Fine and Standard Coarse. I bought mine earlier this summer and it's been a huge help on several projects already.

[Bing]

I would have to think that the nylon/plastic compress' hence the inaccurate torque value. I would just go through their sequence once (2 step process) and call it good. Maybe put some thread locker on the bolts for extra insurance.

[00Beast]

I was thinking about that, might not be a good idea to try and run them down multiple times. If the torque spec is 89 in/lbs, set your wrench to that and get them that tight. If it was supposed to be staged that would be the spec. 89 in/lbs isn't very much to begin with, so staging the torque shouldn't matter. It's somewhere around 9 ft/lbs, you can probably hold the socket in your hand and get it to click at that torque.

[Archon]

Actually, it's closer to 7.5 ft lbs. Chasing the threads in the LIM is very important for proper torque readings. Also, make sure the alignment pins are where they belong.

I start by tightening the bolts to where they just make contact with the UIM, then do a two stage process, starting with about 45 in lbs, then increase to 89 in lbs. Tighten slowly and make sure that you stop as soon as the torque wrench clicks. I then go back and double check the torque readings, again slowly putting pressure on the wrench. I don't think I've ever had to do it more than twice.

Specs do call for thread lock.

Apply thread lock compound GM P/N 12345382 or equivalent, to the bolt threads before assembly.

I just use Permatex blue.

Hopefully, your next one will go better. It doesn't take much extra torque to crack the UIM. A few years back, a member cracked his UIM by following the information in the FSM that had the UIM bolts improperly listed as 11 ft. lbs. I don't recall what year that was, however.

[01bonneSC]

7.41 ft lbs.

[00Beast]

Thanks Jake. I was going off the top of my head, lol.

[01bonneSC]

Thanks Jake. I was going off the top of my head, lol.

No problem, I had to use a calculator

[Vitaminmopar]

Thanks all for the input! On the replacement UIM I will use the two stage torque process, 22 inch pounds and then 89 inch pounds. I'll chase the threads this afternoon and get some thread locker or permatex blue. I have always used a 4 step torque process with the click stop torque wrenches. Guess maybe I should not do that with the UIM. THe APN part is a good replacment part and the folks I spoke with at ineedparts.com and at Graywerks were helpful. Ok off to get a tap set. Thanks again to all.

[Bing]

Glad to hear that you were able to get good service. Hope all goes well second time around.