upper control arm bolt Q

[JOMJ87]

OK i am making new uppers for my MJ and for now they are going to be short arm so cause my plan for long arms isnt quite ready but i want to go wheeling soon. Anyway I bought the small RE super flex joints for the upper portion (the frame Mount) well my dad mesured the stock bolt whol in the stock bushing on stock XJ arms and it says 1/2". My RE joints are 3/8" so there lies a problem. I messured mine as best i could but with a tape you can't get real accurate. SO finally my QUESTION is what is the stock bolt size on the upper mount on the upper arms. Thanks

 

Cole

[rockhardzj]

Bolt thickness?

Luckily, I have some laying around, and they are 1/2" thick, 5/8" head, entire length is 5-3/4", with 1-3/4" threaded I beleive 14 threads per inch.

 

Want a picture?

[87manche]

they're a shade bigger than half inch, a metric bolt.

14mm if I recall.

 

I used half inch gr8 to replace one once, it left some slop in the bushing.

[JOMJ87]

Well the issue i have is the frame mount area. The RE joints are made for 3/8ths or 10mm but the holes in the frame are going to be 1/2". I don't think it would cause to much of a problem but i just want to make sure. Thanks for your help.

 

Cole

[87manche]

depends.

could use some big grade 8 washers around the hole.

[pingpong]

That will cause the clunk you hear ppl refer to in the front end. I am pretty sure RE sells joints with bigger bolt holes. Ideally you want the hole pretty tight.

[Eagle]

UCA bolts are 10mm, lowers I thought were 12mm. But 12mm would be slightly smaller than 1/2" not slightly larger.

 

The holes in the frame at the upper control arm mounts should not be 1/2". If you put 10mm or 3/8" bolts in a 1/2" hole there's no way you will be able to stop the bolt (and arm) from shifting and clunking.

[JOMJ87]

Well Eagle has been the only one to agree with my other findings and messurements but i think i will try 3/8ths and if it is 1/2 then i can go back and redo the mount or something. I already have the joints and i need it in ASAP so i can put the 4.88s in the front. I think i am going to look in a Service manual and see what it lists if it does.

 

Cole

[87manche]

eagle may be correct, I remmeber that I used the imperial size closest to the metric size, it did clunk, and it's probably what toasted the bushing.

[rockhardzj]

eagle may be correct, I remmeber that I used the imperial size closest to the metric size, it did clunk, and it's probably what toasted the bushing.

Well, my jeep sources say metric is the winner. I just did quick measurements with a tape measure.

[Eagle]

Oh, I know the hard way that they are metric. It's just that at my advanced age, remembering what I ate for breakfast is hard enough. Remembering what size bolt I pulled out of a control arm last year is a miracle.

 

Rough equivalents:

 

3/8" is actually 9.x mm

 

1/2" is 12.7 mm. XJ rear spring u-bolts are 12 mm. Thinking they were 1/2", I once tried to use a reversed lug nut to replace a lost nut in a u-bolt. It would appear to thread on okay, but when it came time to tighten it, obviously it just spun.

 

14 mm is 9/16". The same XJ from which the guy lost the axle u-bolt nuts, he also lost the 14mm bolts that go through the shackle and the spring bushing. I couldn't find anything close in 14 mm but I found the right length in a 9/16" grade 8. I had to polish the bolt shank and tap it through with a hammer, but they worked.

[DirtyComanche]

Yes, those bolts are metric. The frame side ones are often torx - which is a big hint as there is very few SAE/UN thread bolts that use that head style. I want to say there's none, but I can think of one application right now - so they may well be common somewhere. Anyways, my point is that on Jeeps the torx are always metric.

 

 

 

 

Anyways, to make the bloody hole the right size I'd suggest a shock bushing sleeve. They make them for most sizes (providing you can find somebody that sells them), and with a little trial and error would allow you to shim up the hole to the right size.

[rockhardzj]

Yes, those bolts are metric. The frame side ones are often torx - which is a big hint as there is very few SAE/UN thread bolts that use that head style. I want to say there's none, but I can think of one application right now - so they may well be common somewhere. Anyways, my point is that on Jeeps the torx are always metric.

 

I'm going to swicht 95% or more of the MJ to SAE/non-torx bolts. I can't stand the damn things. I snap torx bits like a fat kid all over an ice cream cone.

[Mitch]

X2 I love ice cream!

[Eagle]

I'm going to swicht 95% or more of the MJ to SAE/non-torx bolts. I can't stand the damn things. I snap torx bits like a fat kid all over an ice cream cone.

The problem is, then they won't fit. In many applications (such as the control arms) you'll be building in clunks that you'll never be able to get rid of.

 

The preferred solution (IMHO) is to use the correct bolt, and use it with anti-sieze. If you anti-sieze both the threads and the shanks, you should never snap anout bolt or bit.

[rockhardzj]

I'm going to swicht 95% or more of the MJ to SAE/non-torx bolts. I can't stand the damn things. I snap torx bits like a fat kid all over an ice cream cone.

The problem is, then they won't fit. In many applications (such as the control arms) you'll be building in clunks that you'll never be able to get rid of.

 

The preferred solution (IMHO) is to use the correct bolt, and use it with anti-sieze. If you anti-sieze both the threads and the shanks, you should never snap anout bolt or bit.

I didnt mean all SAE, but rather SAE where applicable, welded in metric nuts will still get metric bolts, just not torx head ones... Torx bolts will be replaced to something used with metric/sae sockets, as it's pretty hard to shear/snap/explode a socket compared to torx bits. I understand a few low clearance areas will still require the supid torx junk, so in those cases, tons of antiseize will be used.