knuckle rebuilding questions.

[billstoudt]

i am upgrading my 55 to a MAF disc brake kit, so per the suggestion of other Mud members i decided to take on rebuilding my knuckles while i had it all apart. the whole area was a big goopy mess so i figured it was probably a good idea.

i am a bit daunted but i'm going through the process slowly trying not to mess anything up. i have two books on my cruiser but both are vague on the questions i have. so i have a few questions I'm hoping someone can answer.

My rebuild kit (SOR) came with two felt gaskets a larger diameter thinner grey gasket ( i assume this goes in the back of the knuckle ) and a smaller diameter thicker one. i cant figure out where this second felt gasket goes.

Metal shims

i noticed when i pulled my the knuckle arm off (as well as the piece on the bottom) that there were some metal shims underneath it. my kit came with new shims but there are various thicknesses. what do these shims do and how do i determine which thickness to use.

these shims have 5 small holes in them one on each corner and then one extra hole on one side what is the purpose of these holes which direction does the extra hole go.

GREASE

1 how much to use.
2 what kind to use
3 when do i put it in

 

[scrapdaddy]

Bill,

The best help I can give is, research " knuckle rebuilding " here and in the 40, 55 tech section. Also look in the FAQ , at the top of the 40, 55 tech section. Many, many questions answered there.

Don't mix up your shims. keep the top ones together and the bottom ones together. You can use new ones, but they have to be the same thickness.

Good Luck with it, Ron

 

[billstoudt]

too late i already mixed them up.

 

[billstoudt]

i had already checked the faq (to answer some other questions) but i was unable to find these particular answers.

 

[Pighead]

The correct answer is "Borrow a centering tool"...

 

[scrapdaddy]

Bill, here is what you're probably going to do, since the shims got mixed up. https://forum.ih8mud.com/40-55-seri...-knuckle-centering-tool-instructions-faq.html. I don't know anyone with a centering tool, have to ask around. If the knuckle isn't centered, it will wear out the axle seals.

 

[Pighead]

There's usually a thread in 40/55 tech "borrow the centering tool"...

 

[nuclearlemon]

just a quick guess on your thicker felt gasket...it's for a drum setup. they took a "square" felt gasket in their flanges.

the shims are for your trunnion setup...as mentioned, you now need a sst to set them up since you mixed them up....although, if you can find what standard was, you may be fine...sorry, i can't remember std measurements.

grease the crap out of the knuckle housing/birf housing with a good wheel bearing grease(moly preferred), but don't over pack. remember too much equals too much heat. just a lot is good.


my apologies on the maf setup.

 

[billstoudt]

why apologies with the maf setup?

 

[tucker74]

Unfortunately as others have said, you're supposed to put those shims back exactly like the they come off Now you get to learn the joys of a knuckle centering tool. As far as your other questions, here is the complete blow up of your knuckle:

If you look at #80 left to right it goes: Your half moons, felt gasket, rubber gasket, metal gasket (fits in the groove in the back of the knuckle). The second felt is #29 in the pic, you only need this on pre-'75 knuckles for the drum so you wont use it. I use a good moly grease in the knuckle, some people go nuts here but there is no need. If you are separating the birfs pack the bell before you set the clip, if not rotate the joint around in a circle while you spatula grease into the joint. I form a mound of grease on the back of the birf bell against the axle, stab it and spatula in grease until the axle bell is 1/2-3/4 packed. You want to make sure and do this after you have assembled the knuckle and trunions, you will want to measure your knuckle pre-load with all the gaskets etc anyway.

Good luck!

Tucker

 

[Gonzo55]

What's the result of just guessing ?

 

[tucker74]

What's the result of just guessing ?

As long as your pre-load is good you are probably fine, can take several tries to get it that way and removing trunions can be a PITA. If you get it shimmed too far out of whack it can cause your birfs to wear.

Tucker

 

[scrapdaddy]

The axle seal will start leaking first, I think. No personal experience with mixed up shims.

If you would just do a guess, then it might be a good idea to get the Marlin HD Seal. Maybe it can stand up to alittle off centering.

 

[Gumby]

The axle seal will wear prematurely if the shims aren't right. How much prematurely is debatable especially on a 4wd as opposed to an AWD.

 

[nuclearlemon]

why apologies with the maf setup?

a lot of money for a kit that now means custom components (not readily available if things go wrong), doesn't address any of the weakness issues (if you stay small tires, or don't wheel to hard not that big of a deal) and doesn't fit with oem rims.


as for the shims, whatever you do, DO NOT put the caps on with no shims. if you tighten them down, you will essentially seize the cap onto the trunnion bearing and will most likely ruin the bearing. if you search, you will find most people have found a common measurement, can't remember what it is. that would be a best spot if you plan on assembling with no recentering tool.

for grease, you want quite a bit, but don't pack the housing cavity full.. too much grease is jsut as bad as not enough. it will retain heat. pack the birfs full, and the housings and hubs about 1/2

 

[Gumby]

Vs. a 78 disk axle that can be had complete with big knuckles and all the correct parts with steering arms for $200 tops.

Too much grease in the housing will blow through the felts and make a mess. And might blow through the axle seal and get in the gear lube. About half full on the housings and I like moly synthetic grease. 3-4 tubes will do the trick.

A spatula and nitrile gloves will be your friend.