1977 FJ 40 Knuckle Shim Question

[D'Animal]

I'm still a newby I guess but I have done probably 15 to 18 FJ front knuckle jobs in the past 6 years. This one has me stumped.

I took it apart and it had one thick on top and one thick on bottom on both sides. The trunion bearing races were imprinted with the bearing needles. No grease in the knuckle housings at all, just some oil. Rig had been sitting for 9 years so i figured the weight of the rig had something to do with it.

So

New Marlin HD Axle seals.
New Wheel Bearing/Knuckle Bearing kit from Marlin.
New Seal Kit from Marlin.
New Small Pattern Shim kit from Valley Hybrid (OrangeFJ45)


Everything is cleaned and reasssembled. I am having a hard time getting the preload on the knuckle or trunion bearings set.

I started with one thick and one thin on top and bottom.
This gave it 0 preload.

I took the thin ones out and reassembled with just the thick on top and bottom.
This gave it 0 preload.

I took the thick ones out and reassembled with just the thin on top and bottom.
This gave it 2lbs preload.

I took the thin ones out and reassembled with no shims on the top and bottom.
This gave it 8lbs preload.


I generally set them 12lb to 14lbs.

The knuckle studs are torqued to 60ft lbs.

Has anybody had to set one up with no shims?

 

[Shipwreck]

The biggest error I see in your method is that you are changing the bottom shim. The bottom shims align the knuckle with axle housing. This keeps the axle shaft centered in the inner axle seal and the spindle bushing. Once this measurement is determined it should not change. The top shims are used for setting the trunion bearing preload.

If you don't have the SST for centering the knuckle, then I would go back to replacing the original thick shim in the bottom and then adjusting the upper shims until the preload is correct.

 

[D'Animal]

But with no shims on the top or the bottom I still have no preload. With equal shims top and bottom, the knuckle should be centered, right?

I will take another try at it this morning. I have to be missing something.

 

[bucfan]

D'Animal,

I get what your saying because when I did mine recently, thinner shims gave it more preload (I think that is what I remember). So in theory, no shims=max preload. Could you been sent the wrong bearings or wrong bearing races where the diameter was the same but not the thickness? Good Luck.

 

[D'Animal]

I have another set of bearing and races I will be trying this morning. These are the Koyo's. I can't remember what the other ones were but I think the same.

 

[dgangle]

Sounds like you have the right thought pattern going and no I have never set one up without the need for shims.

The last one I did a few months ago I borrowed a SST because I kept getting leaking inner axle seals. I turns out I was WAY OFF on the shims. I used the HD Marlin IA seals too and hope to not have to do this again for a long time. What was so surprising to me is that I kept the shims stacks virgin from the donor minitruck for the FDB and I know they were never changed by the PO has he bought the truck new in 1979.

I guess what I am trying to say is get yourself the tool and see what it says because it won't lie. If you indeed have a situation that requires no shims and you need MORE preload, one option for you may be to machine both knuckles on the shim surfaces an equal amount to move the trunion caps inward and necessitate the use of shims to get the desired preload. Who knows, maybe your knuckles were machined on a Monday morning by a hungover jap? Measure the knuckles from the machined surface to machined surface. This "B" dimension as called out in the FSM proceedure should be approx 6.502"

One last thing I just thought of. Make certain that the trunion bearing caps are being pulled down comnpletely and are not being help up somehow by interference or a large bur possibly by some PO separating them with a chisel?????? The wrong trunion bearing/races could be key too. Let us know what you determine the problem to be.

 

[D'Animal]

Another set of New trunion/knuckle bearing and all is good.

One thick and one thin on bottom. One thick on top.


13lbs