Help with Front end Pop-Solved! Finally.

[AlpineAccess]

OK all, I just got back from a 5 mile test drive that would have caused dozens of popping events on the cruiser and I think I got this one solved.

I've been saying for awhile it felt "torsional" as in frame twist and after finding all four bolts on the SLEE differential cross member at around 30-40ft lbs of torque and tightening them I no long am getting the noise. I know I torqued these to spec when I installed it, but that was 30-40k ago and they use a compression washer as well as an open "C" Channel design on the area the bolts sit.

I would recommend retorquing these bolts after a few thousand miles. I increased the torque to 75ft lbs.

I am going to drive it a few more days and if this is actually the issue, I am going to remove each nut and add locktite and reinstall to 75ft lbs.

I did test the LCA bushings and there is zero movement. I verified I did get the bushing spacer in there on them, they were all torqued to 170ft lbs, and they were tightened at ride height.

@Patassa do you have a diff drop? Hope its the same thing I ran into because its easy to sinch those guys down.

 

[Patassa]

OK all, I just got back from a 5 mile test drive that would have caused dozens of popping events on the cruiser and I think I got this one solved.

I've been saying for awhile it felt "torsional" as in frame twist and after finding all four bolts on the SLEE differential cross member at around 30-40ft lbs of torque and tightening them I no long am getting the noise. I know I torqued these to spec when I installed it, but that was 30-40k ago and they use a compression washer as well as an open "C" Channel design on the area the bolts sit.

I would recommend retorquing these bolts after a few thousand miles. I increased the torque to 75ft lbs.

I am going to drive it a few more days and if this is actually the issue, I am going to remove each nut and add locktite and reinstall to 75ft lbs.

I did test the LCA bushings and there is zero movement. I verified I did get the bushing spacer in there on them, they were all torqued to 170ft lbs, and they were tightened at ride height.

@Patassa do you have a diff drop? Hope its the same thing I ran into because its easy to sinch those guys down.

I do have one, I have the Trail Tailor version. I'll try that, thanks for the report back.

 

[AlpineAccess]

Put 20 miles on tonight and confirmed the noise is gone.

 

[AlpineAccess]

@Patassa Any luck?

Spoke with Paul @2001LC yesterday via text and he did note that he has never found diff drop bolts to have loosened if they were torqued to spec originally.

Would be interesting to see if you ran into this as well. I am highly confident I did torque to spec as every one of these bolts was at 35-40ft lbs when I checked them before cranking down - and my safety marks with my metal pen were still matching.

 

[Patassa]

@Patassa Any luck?

Spoke with Paul @2001LC yesterday via text and he did note that he has never found diff drop bolts to have loosened if they were torqued to spec originally.

Would be interesting to see if you ran into this as well. I am highly confident I did torque to spec as every one of these bolts was at 35-40ft lbs when I checked them before cranking down - and my safety marks with my metal pen were still matching.

Haven't gotten a chance yet, working 7-12's and I have an aluminum skid plate in the way preventing this from being a quick check. Pretty sure I've skipped over those bolts when I retorqued all the other suspension and bushing bolts though so I'm crossing my fingers.

 

[Patassa]

@Patassa Any luck?

Spoke with Paul @2001LC yesterday via text and he did note that he has never found diff drop bolts to have loosened if they were torqued to spec originally.

Would be interesting to see if you ran into this as well. I am highly confident I did torque to spec as every one of these bolts was at 35-40ft lbs when I checked them before cranking down - and my safety marks with my metal pen were still matching.

Unbelievable. After all the blood sweat and tears I've gone through it was indeed these four bolts. As soon as I turned the first one, I was thinking, well that's just one loose bolt, this can't be it. But all 4 were loose, probably sitting around 20 ft lbs, tops. I cranked them all to 80 ft-lb. Completely eliminated my pop, thanks for the suggestion! I'm so happy with my Cruiser again. Keeping this sucker for another 10 years!

 

[AlpineAccess]

Unbelievable. After all the blood sweat and tears I've gone through it was indeed these four bolts. As soon as I turned the first one, I was thinking, well that's just one loose bolt, this can't be it. But all 4 were loose, probably sitting around 20 ft lbs, tops. I cranked them all to 80 ft-lb. Completely eliminated my pop, thanks for the suggestion! I'm so happy with my Cruiser again. Keeping this sucker for another 10 years!

View attachment 3158350

Fantastic! Really glad that worked out and I share the same sentiment about how great it is to drive again!


For posterity, do you know about how many miles you have on your diff drop install?

 

[Patassa]

Fantastic! Really glad that worked out and I share the same sentiment about how great it is to drive again!


For posterity, do you know about how many miles you have on your diff drop install?

Looks like it's been installed since March of '21. I do about 20k-25k miles a year, so 30-32k+ miles give or take.

 

[AlpineAccess]

Looks like it's been installed since March of '21. I do about 20k-25k miles a year, so 30-32k+ miles give or take.

Exactly the mileage I have on mine; around 35k with a bit of trail use mixed in. It's nothing wrong with the part installed but I'm wondering if the application should have locktite and/or call for a higher install torque spec.

 

[Patassa]

Exactly the mileage I have on mine; around 35k with a bit of trail use mixed in. It's nothing wrong with the part installed but I'm wondering if the application should have locktite and/or call for a higher install torque spec.

Agreed. I can't remember if I used a trail tailor provided torque number or if I re-used the values from the service manual actually since the bolts were re-used (not part of his kit)

 

[chudly]

wow I've been chasing this for months too. will check the diff drop!

 

[Seth7843]

I do not have a diff drop but I decided to go check the 4 bolts holding the diff crossmember. One but was about to come off and was barely finger tight. The 3 other bolts were not torqued enough. I went ahead and checked the other diff mount bolts and the highlighted nuts and bolts were loose. I test drove it and this seemed to make the popping worse. I believe it might be the AHC “shock” bushings which clearly are blown and have a lot of movement. To be continued…

 

[Indiana80]

Unbelievable. After all the blood sweat and tears I've gone through it was indeed these four bolts. As soon as I turned the first one, I was thinking, well that's just one loose bolt, this can't be it. But all 4 were loose, probably sitting around 20 ft lbs, tops. I cranked them all to 80 ft-lb. Completely eliminated my pop, thanks for the suggestion! I'm so happy with my Cruiser again. Keeping this sucker for another 10 years!

View attachment 3158350

Fighting a popping noise, also. Have Slee diff drop installed. I’ve torqued to 60 or 70 ft lbs- no change. I think I’ll try running the 4 bolts up to 80 ft lbs. maybe loctite the threads, also. Do you recall if you tightened from the bolt head or the nut head? I didn’t install the diff drop on mine (PO has installed by Slee), so I’m not sure if bolts or nuts are staked.

 

[Patassa]

Fighting a popping noise, also. Have Slee diff drop installed. I’ve torqued to 60 or 70 ft lbs- no change. I think I’ll try running the 4 bolts up to 80 ft lbs. maybe loctite the threads, also. Do you recall if you tightened from the bolt head or the nut head? I didn’t install the diff drop on mine (PO has installed by Slee), so I’m not sure if bolts or nuts are staked.

Hate to say it but if you're around 60/70 this likely isn't you're issue. I think I had to use the heads due to space constraints.

 

[excessive]

i think someone else had a popping issue and it turned out to be the body mounts. cheek those too

 

[Indiana80]

i think someone else had a popping issue and it turned out to be the body mounts. cheek those too

I haven’t checked body mounts- those are next on my list. Tighten? Or spray them with lubricant? Or both? I would probably spray with Fluid Film.

 

[Indiana80]

New best friend, nice to meet you.

You guys are all my best friends. I’m fighting the same singular pop when turning (sometimes), when accelerating at city driving speeds (sometimes), when braking at slower speeds (sometimes). I’ve tightened everything I can think of. Wondering if it is the SPC UCAs? Thinking of throwing some Dobinson UCAs in to see what happens.

 

[mckunz]

My most recent pop had come from my UCA cam bolts not being torqued from my last alignment; check those!

 

[Indiana80]

My most recent pop had come from my UCA cam bolts not being torqued from my last alignment; check those!

Thanks, if I recall, those cam bolts have 2 nuts on the ends. Do you have to loosen the outer nut, then tighten the inner nut, then retorque the outer nut? Also, how can this adjustment be made without messing up camber alignment? I have SPC UCAs. I suspect that’s where noise is coming from.

 

[mckunz]

Thanks, if I recall, those cam bolts have 2 nuts on the ends. Do you have to loosen the outer nut, then tighten the inner nut, then retorque the outer nut? Also, how can this adjustment be made without messing up camber alignment? I have SPC UCAs. I suspect that’s where noise is coming from.

Just check the nuts and torque them while ensuring the bolt does not adjust, which it shouldn't.