Spring Perch issue on dana 35

[Airsuperiority]

Alright, the saga of random crap that is wrong with my MJ continues! I recently put on a set of beautiful turbines. As you guys probably know, the backspacing is quite different than aftermarket wheels. Well, it turns out that my leaf spring perches must be welded on in uneven spacing because passenger side rear tire (31x10.5) sits close enough to the frame that I can see signs of rubbing. I assume this is occurring during flex or turns. The distance from inside bas of drum to outside perch on driver side is 5 3/8 in and the distance from same location to location on passenger side is 5 in. Is this normal? From my alignment diagnosis my thrust angle is -0.58 degrees. The axle seems shifted towards the driver side. Never noticed this issue until I put stock rims on the wider tires. 

[Pete M]

3/8" is not enough to cause this.  look at your shackles from the rear and see if they are straight or if the bushings are wasted and the axle is pushed to one side. 

 

a fix for the rubbing can be found with a pair of 1.25" spacers.  as a bonus, it'll make the rear tires look more like the front with regards to the flare coverage.  

[Airsuperiority]

On 8/10/2024 at 4:07 PM, Pete M said:

3/8" is not enough to cause this.  look at your shackles from the rear and see if they are straight or if the bushings are wasted and the axle is pushed to one side. 

 

a fix for the rubbing can be found with a pair of 1.25" spacers.  as a bonus, it'll make the rear tires look more like the front with regards to the flare coverage.  

thanks Pete. which bushings are you referring to. Also, I have been looking for a pair of 1.25 spacers. 

[Airsuperiority]

it’s probably more like almost an inch. it is visible from the rear that the left tire is sticking out more than the right tire. the right tire is pretty close to the frame. 

[Pete M]

2 hours ago, Airsuperiority said:

thanks Pete. which bushings are you referring to. Also, I have been looking for a pair of 1.25 spacers. 

 

the leaf spring bushings.  how leaning are the leaf springs if you look at them from straight behind?

[ghetdjc320]

BORA makes some of the best quality spacers in almost any size you need

[88towmanche]

I used these off of Amazon - no complaints

 

[Airsuperiority]

2 hours ago, Pete M said:

 

the leaf spring bushings.  how leaning are the leaf springs if you look at them from straight behind?

they are leaning enough to see that the axle looks shifted towards the driver side. the leaf springs are only 2 years old so the bushings should be alright. 

[Airsuperiority]

1 minute ago, Airsuperiority said:

they are leaning enough to see that the axle looks shifted towards the driver side. the leaf springs are only 2 years old so the bushings should be alright. 

the space between tires and frame is 1 and 1/2 inches driver side rear and 1 inch pass side rear. 

[WranglerMangler]

My 31-10.5-15s on 01 XJ wheels rubs pretty significantly on the “frame” behind the rear tires. Has a factory 44. Haven’t measured if it’s centered or not. Black spray paint worked wonders for me, until it flexed out again. 

[Pete M]

can you snap some pics of your bushings, leafs, and leaf perches?

 

but I think the solution is going to be some spacers.   

[Eagle_SX4]

I got some 1.25 wheel spacers and my tires (31x10.5) don't rub any more. Probably the way to go.

1 hour ago, Airsuperiority said:

they are leaning enough to see that the axle looks shifted towards the driver side. the leaf springs are only 2 years old so the bushings should be alright. 

Sounds like your shackles might be bent. Make sure they are straight up and down. Some pics would be helpful.

[Airsuperiority]

15 hours ago, Eagle_SX4 said:

I got some 1.25 wheel spacers and my tires (31x10.5) don't rub any more. Probably the way to go.

Sounds like your shackles might be bent. Make sure they are straight up and down. Some pics would be helpful.

the schackles seem fine but i can see some sway in the u-bolts. i provided a pick of just the drivers side u-bolt. Its hard to tell if the perches were welded on wrong or not. I know that they were welded on because it is not factory welding on them. might i be able to run just one spacer on the side that rubs or do i need to run two?

[Eagle_SX4]

Looks like your bushings are worn out. The spring should be centered in the shackle.the u bolts should be straight. New u bolts and new leaf spring bushings might fix your issues.

[Airsuperiority]

16 hours ago, Pete M said:

can you snap some pics of your bushings, leafs, and leaf perches?

 

but I think the solution is going to be some spacers.   

Hedy pete, I snapped some shots below. Thanks

[Airsuperiority]

2 minutes ago, Eagle_SX4 said:

Looks like your bushings are worn out. The spring should be centered in the shackle.the u bolts should be straight. New u bolts and new leaf spring bushings might fix your issues.

Thats strange though now? The bushings were new with the 1 ton leaf kit I put on 2 years ago. Seems kind of fast...

[Airsuperiority]

10 minutes ago, Eagle_SX4 said:

Looks like your bushings are worn out. The spring should be centered in the shackle.the u bolts should be straight. New u bolts and new leaf spring bushings might fix your issues.

I measured from the drum to the edge of each perch bracket and on one side it is 4 1/2 inches and the other side it is 5 inch. To me, that means that the welded brackets are a half inch off or at least one of them is.

[Eagle_SX4]

29 minutes ago, Airsuperiority said:

I measured from the drum to the edge of each perch bracket and on one side it is 4 1/2 inches and the other side it is 5 inch. To me, that means that the welded brackets are a half inch off or at least one of them is.

 

Put the axle on some jack stands and remove the wheels. Hang a weight (nut or bolt on a string) off the frame centered over the axle and take some measurements just to see where your axle actually is in relation to the frame.

 

Fix the easy stuff first (bushings and u bolts) then see where the axle is compared the the frame. If it is still 1/2 inch off then you might need to look into getting new perches welded on to the axle.

 

[Pete M]

I would just add spacers and call it a day.   even if you get it centered, you'll still likely have tire rub with the fat rubbers on stock rims. 

[ghetdjc320]

1” spacers are about a perfect fit to fill out the rear wheel well. Maybe throw on some new u bolts also. Don’t get too obsessive about centering your rear axle, less you find the entire jeep is out of alignment from the factory . Seriously though, the build standards were by no means exact. Little by little you can replace any damaged or worn items but those tires are always going to rub unless you add spacers or change wheels to something with less backspacing. 

[Airsuperiority]

On 8/14/2024 at 7:49 PM, Pete M said:

I would just add spacers and call it a day.   even if you get it centered, you'll still likely have tire rub with the fat rubbers on stock rims. 

Hey Pete- Circling back here. What would your advice be on using one spacer on the passenger rear for a DD. Still trouble shooting the issue and have been super busy so I am just now getting back to it. I feel if I go with two spacers then i’m still gonna have the left side sticking out further and further exacerbating the thrust line issue. Looking into new bushings and u bolts also. I also need to measure the perches to make sure they are 42 inch center to center. Thanks 

[Pete M]

they sell them in pairs so you can mix and match and see what works best for you.