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1995 Jeep YJ Wrangler suspension, brake and axle/wheel overhaul DIY


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Moses and @biggman100 @BadDriver4x4 thanks for taking the time (a full year ago!) to respond to my inquiry.  A little update:

I found a mechanic out in Suffolk County, NY who is supposedly the local Jeep expert.  I drove the hour to visit, nice guy, knows his stuff, but I think he was a bit un-enthused about me supplying all of my own parts, and he has a full schedule - and he knows that an picky, educated customer with a rusty Jeep is a bad value proposition! He never got back to me with a quote.

Well, arm be damned, I decided to take my time and do the work myself.

Some parts:

- Full brakes (calipers/rotors, drums/cylinders, new soft lines)
- Axles (front u-joints (Spicer), ball joints (Spicer), knuckles, hubs (Timken), bolts, lug nuts)
- Susprension (Old Man Emu springs/bushings/shackles/u-bolts)
- Steering linkages/links
- Plus all-new hardware (McMaster), and MOPAR parts where they made sense or where they are still available.  Besides the springs it is essentially stock, just a mild lift.
- Lastly, some brand-new MOPAR lamps & lenses, and a nice new Made in USA "Softtopper": http://www.softopper.com/jeep-suv-tops/jeep-wrangler-yj

So far I have taken her all apart and I am just about complete with rust removal & treatment (POR-15, I couldn't pass on the opportunity to tackle some rust - dropped the tank too).  I am using a lot of Omix-Ada parts also, and am pleased with the quality. I also am impressed with the Centric calipers, which are nicely zinc-plated.

The job is taking longer than anticipated (going on 3 weeks) but I can not wait to experience the difference, "before & after", after 230,000 hard miles. Cheers!

Some photos here & attached: http://imgur.com/a/GXhzV

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alheim...Congratulations on this major undertaking—by yourself!  Wow, you're performing some serious work on your YJ Wrangler...I'm impressed with the quality parts and degree of coverage here.  (The steering knuckles needed replacement in addition to the unit hubs?)  You have taken critical bolts and other safety details into account.  Pleased to see Timken and Spicer quality.

You've certainly provided plenty of work space beneath the Jeep.  Stands stretched to the max on wood platforms...Is the Jeep steady and stable?  By doing the work yourself and saving sublet labor costs, you have funding for quality stands and other safety equipment.  Smart!  Are you using a YJ Wrangler factory service manual for guidance?  They're available used at eBay and other sources...a good investment.

Keep us posted, the photos are excellent and encouraging to others...Thanks!

Moses

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Moses, thank you.

The Jeep looks precarious - but is quite stable.  It would be nice to take the "lift" to the next level with a scissor lift or larger jack stands.

The existing steering knuckles have significant divots worn into them where the brake pads slide on the knuckle. I am aware that I can weld & file as a repair, but I am trying to get this done reasonably quickly and don't want to break out the welder.  They weren't cheap at $80/ea but they are a nice, shiny compliment to the unit hubs.

Indeed, I have a factory service manual!  And a Jeep parts catalog.

Speaking of unit hubs: I read your article where you replaced the unit hubs on an XJ: http://www.4wdmechanix.com/XJ-Cherokee-Front-Wheel-Hub-Replacement?r=1

I quote:

Unit-Bearing-171.jpg

"llus. 17: A light coat of protective, heat resistant paint will help prevent rusting. When using paint in this manner, apply a thin, even coat and do not layer. After torquing wheel nuts in place, drive the vehicle briefly and re-torque nuts to compensate for paint settling."

This is a nice finish to a thorough job, and I might use your idea on the new unit hubs & knuckles.  I like the coating on the exposed threads of the axle shaft and hub bolts.  May I ask, what paint did you use?  I am considering Eastwood's Chassis Black, but it is not heat resistant.  Maybe an epoxy primer?  I will be sure to re-torque the lugs as suggested.

I'll be sure to update in a week or two.  Thanks again.

Alex

 

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alheim...You're doing all the right things with the right resource books as well...Great!  Good call on the new steering knuckles, these are forgings and require special consideration if built up with weld and resurfaced.  We can discuss that process at the welding forum if anyone is interested.  For practical purposes, you made a wise choice kicking in the $160 to assure proper brake caliper movement on the knuckles...The old knuckles will make good scrap.

Glad you have a stable platform to work under.  I had a wonderful Forward 9000# asymmetrical lift at our former shop (depicted in many of the magazine's articles and my later books).  We downsized in 2009, and I only miss one item: the lift!  My current studio/shop is just under 500 sq. ft. while the shop in my books and articles was 1800 sq. ft. plus a 600 sq. ft. office with additional 600 sq. ft. of mezzanine for storage, which I managed to fill up.  With our 2009 move, we decided that less is more, and it's gratifying to see how much you can get done with less square footage.  My current shop space is also more relevant to DIY folks and smaller shop owners who are readers and viewers at the magazine and these forums.  I'm doing Vimeo On Demand how-to rentals now, and the shop/studio is optimal for these projects and filming videos.

With that clarified, I have looked at the OTC Tools truck lifts that lift from the tire bases: https://www.otctools.com/products/mobile-vehicle-lift-system.  Pretty slick yet spendy, a pair of these rates 20K pounds and will lift the vehicle 24" from the ground at the base of the tires.  You'd still need chassis or axle stands, an additional expense.  

As for painting the unit hubs and hub bolts, I'm not clear how thick Eastwood Chassis Black lays down.  Interesting that you mention epoxy primer, I became a real fan of this for transmission cases and other iron.  Its only drawback is lack of UV resistance.  Epoxy two-part primer works on parts that, literally, never see the light of day!

The caveat with any paint, as I shared in the photo illustration, is that you do not want paint to prevent flush fit of parts like a transmission face to the bellhousing face—or your unit hub flanges to the dust shields—and wheel rim mounting flanges to the unit hub faces.  A thin coat of paint, perhaps a flat black (optional heat resistant) primer, would work well here.  The idea is rust prevention, so a rust proofing primer makes sense.  Unit hubs get toasty but not like brake parts.  On brake drums, I do use an engine enamel, typically ceramic content, that simply needs to be applied thinly and prudently to the drums' outer surfaces.  

On this note, I'm not a fan of powder coating beyond limited and sensible uses.  While body armor or a tire rack can benefit greatly from powder coating, wheel flange nut seats are not a good candidate!  Any place that powder coating can "pound down" in thickness is not a place for powder coating.  Like wheel nuts coming loose because of powder coated wheels and nut seats that break down.  Unless a product calls for powder coat, it should not be used.

Also, powder coating can look deceiving.  On some surfaces, if rust forms inside the metal (like a boat railing or even a Jeep frame in salty Rust Belt regions), the powder coating may not exfoliate like paint and primer would.  Exfoliation sends a signal that perforation is well under way.  With powder coating, that message might come too late.  Powder coating is not practical for the railings of a sea-going boat; the railing could look okay then suddenly break in two pieces under weight.

Moses

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  • 1 month later...

I am surprised to hear that your new shop has no lift!  Thanks as always for the advice.  Maybe one day I can afford te OTC truck lifts, but as a shadetree mechanic with no garage and only a dirty driveway, that will have to wait.  Seems like a good option for you, however.


A quick update:

Steady but slow progress due to two weekends New York 20-degree weather, plus a snowstorm, and I was out of town for awhile.  The worst work is complete, namely the endless scrubbing/cleanup, and rust proofing (with POR-15, the end product looks great).  I have installed the new springs / shackles / bushings, and reinstalled the axles so that I could attempt removal of the the previously-seized axle hub nuts.  After weeks of soaking with penetrating oil, and the purchase of a 3/4"-drive 36mm socket, they came off with minimal effort.  Finally, I removed the unit hubs and knuckles.

 

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However, I may have a problem and I am looking for advice.

While replacing the axle u-joints on the bench, I test fit the new Timken unit hubs (PN 513084) into the new Crown Automotive steering knuckles (52067576 & 52067577).  I noticed that it wasn't a press fit - the hub easily slid into the knuckle, with a tiny amount of play, about 0.5mm  - a nice fit, but there definitely is a touch of movement - not press fit by any means.

I also test fit the Timken unit hubs in the removed factory Mopar knuckles.  Here, the unit hubs also slipped into the knuckle with with minimal effort, no "pressing" required, however there was just about zero play.

Is this correct?  When I removed factory hubs from the factory knuckles, it was a tight fit, and took a lot of pounding on the loosened hub bolts to remove.  Maybe that was mostly rust filling a tiny gap with time, but should there ANY play at all?  The 3 hub-to-knuckle bolts are only 75 ft-lb each (compared to 5 wheel lugs nuts at 100 ft-lb each).

If this is improper, I wonder if it is the Crown knuckles, or the Timken unit hubs. I avoid Crown parts; these knuckles are the only Crown bits used for my overhaul, but admittedly these cast knuckles do appear to be nicely made - the casting looks as good as the factory Mopar knuckle.  There are extra holes drilled & tapped, presumably for other similar vehicles.  These were ~$80/each.  The only other knuckles available are Dorman, or Mopar.  I found Mopar knuckles for about $170/each (an extra $180+).

If this is normal, great.  If not, I'll happily buy Mopar - I am not sure why I didn't in the first place.  I am now questioning the quality of the Crown knuckles and the Timken unit hubs altogether, but as mentioned they do appear to be quality parts otherwise.

Regarding cast parts, is there a really difference in quality between brands?

I think I will buy SKF unit hubs, and Mopar knuckles, so that I can properly evaluate and compare.

Alex

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Responding to your questions, Alheim...See red highlighted comments:

On 4/7/2017 at 6:46 AM, alheim said:

However, I may have a problem and I am looking for advice.

While replacing the axle u-joints on the bench, I test fit the new Timken unit hubs (PN 513084) into the new Crown Automotive steering knuckles (52067576 & 52067577).  I noticed that it wasn't a press fit - the hub easily slid into the knuckle, with a tiny amount of play, about 0.5mm  - a nice fit, but there definitely is a touch of movement - not press fit by any means.

I also test fit the Timken unit hubs in the removed factory Mopar knuckles.  Here, the unit hubs also slipped into the knuckle with with minimal effort, no "pressing" required, however there was just about zero play.

This should be a zero-play fit.  You're right...You need the unit hub assembly to stay on center with the knuckle hole acting as an "indexing" bore.  The three bolts (new and torque'd OE replacement bolts recommended) keep the bearing flange from rotating.  Weight is supported by the interference or close fit.  The knuckle bore and hub flange fit assures knuckle/hub load support.

Is this correct?  When I removed factory hubs from the factory knuckles, it was a tight fit, and took a lot of pounding on the loosened hub bolts to remove.  Maybe that was mostly rust filling a tiny gap with time, but should there ANY play at all?  The 3 hub-to-knuckle bolts are only 75 ft-lb each (compared to 5 wheel lugs nuts at 100 ft-lb each).

Yes, sounds correct torque for this thread size.  Use new OEM replacement bolts and Loctite.  The flange head OE bolts often come with Loctite on threads.

If this is improper, I wonder if it is the Crown knuckles, or the Timken unit hubs. I avoid Crown parts; these knuckles are the only Crown bits used for my overhaul, but admittedly these cast knuckles do appear to be nicely made - the casting looks as good as the factory Mopar knuckle.  There are extra holes drilled & tapped, presumably for other similar vehicles.  These were ~$80/each.  The only other knuckles available are Dorman, or Mopar.  I found Mopar knuckles for about $170/each (an extra $180+).

If this is normal, great.  If not, I'll happily buy Mopar - I am not sure why I didn't in the first place.  I am now questioning the quality of the Crown knuckles and the Timken unit hubs altogether, but as mentioned they do appear to be quality parts otherwise.

Regarding cast parts, is there a really difference in quality between brands?

I think I will buy SKF unit hubs, and Mopar knuckles, so that I can properly evaluate and compare.

I like your thoroughness and safety concerns...Let us know your findings with the Mopar knuckles and SKF unit hubs.  I've used SKF hubs, they've been on our XJ Cherokee for 70K miles running 33" tires.

Alex

 

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Moses, thank you.  An update:

First, I received my Mopar knuckles.  They clearly are a nicer product than the Crown hubs.  Nicer finish, slightly better machining at key points (caliper/pad slides, connection to tie rod ends, etc).  The knuckle has markings inscribed, I suppose these indicate the manufacture / inspection dates (?), whereas the Crown has no markings whatsoever.  All holes/taps are nicely centered on the casting, whereas they might be off-center on the Crown - they are still properly located/oriented in relation to each other but it doesn't look as nice.  I will not say that the Crown is a bad product, but the Mopar is nicer.  Crown was about $80/ea, these were ~$170 each.  I will splurge on the Mopar parts here, and will return or sell the Crown parts.


Second, I received the SKF unit hubs.  They are very nice.  Compared to the Timken, it is tough to say what is the better product, they both appear to be top notch. The SKF has a larger seal at the back/inner side, with no recesses where water or mud might collect, but the bigger seal might be more vulnerable to damage.  The Timken has more machined surfaces, not sure if this is good or bad.  The SKF is a darker color of steel.  The SKF turns more easily by hand - however I presume that the Timken's will break in nicely.  The Timken has more numbers/codes engraved into the front than the SKF.  I wonder which is more corrosion-resistant?


Lastly, regarding fit of the unit hubs into the knuckles.

a) The Timken units fit into both the Crown & Mopar knuckles with the same, tiny bit of play - maybe 0.5mm at most - a good fit but NOT press fit.

b) The SKF hubs fit in exactly the same manner into both sets of knuckles - with a touch of play.

c) The cheapo, economy unit hub that I bought & returned from my local shop also fit into both knuckles with the same touch of play.

 

Therefore, I must conclude that the tiny bit of play between the unit hubs & knuckles is acceptable.  I will use the Timken unit hubs into the Mopar knuckles.

 

Some photos.  Crown on left, Mopar right:

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Crown caliper/pad slides:

G1CsGyk.jpg

Mopar:

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Crown:

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Mopar:

uQL57j7.jpg

SKF left, Timken right:

M2nMDFv.jpg

r6HZxou.jpg

SKF:

cNsxre5.jpg

Timken:

5DXO8bz.jpg

 

Edited by alheim
Clarity & photos
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Very interesting!  You went the distance to get the best parts available in the current market. 

How do the OEM (original) hubs fit into the new Mopar knuckles?  If the old unit bearings are original, the fit should be telling...Be sure the old hub flange casting is clean of debris and scale.

I've used the SKF type and like the seal and bearing size.  It looks like the SKF bearing is larger than the Timken.  Your take?

Thanks for sharing these details, Alheim!

Moses

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My pleasure, thank you.

I don't know enough about bearing design to tell if the SKF bearings are larger than the Timken.  Looking again, however, I do like how the SKF wheel flange meets the bearing at visible, parallel faces, whereas the Timken (& Mopar?) units have a taper that obscures the inner seal - but you can't really see this in my photos.

Unfortunately I discarded the old Mopar unit hubs before I knew this was an issue, therefore I can not test fit into the new Mopar knuckles.  The Mopar hubs (53007449) go for nearly $250/ea (edit: ~$135 on eBay) - don't tempt me ...

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Buying Mopar unit bearing hubs just to check the fit would be excessive.  Even though this fit should be reasonably close for a backup, I do not recall a need for pressing (pulling in this case) original Jeep YJ Wrangler or XJ Cherokee unit hubs loose from the knuckles. 

By contrast, I covered OTC Tools at the 2016 SEMA Show, and they offer two specialized puller/remover tools for Dodge Ram truck unit hubs.  Some unit hub applications are a semi-press fit and often require special tools to remove the unit hub.  Here's that tool set example:   https://www.amazon.com/OTC-6576S-Dodge-Hub-Service/dp/B00K8WNLQK

I'm guessing that you had no difficulty separating your Jeep YJ Wrangler unit hubs from the knuckles?  If that was true, the fit you're finding is apparently "normal".  SKF and Timken build to close tolerances.  You stepped up for better tolerance and quality Mopar knuckles.  Though raising questions, this must be the right fit for this application.

Moses

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  • 2 weeks later...

I am just about done with this project, I have everything together besides the brakes, steering linkages, cotter pins, torquing of some bolts, and a test drive!  Saturday will be the day, hopefully.

Ultimately I decided not to paint the knuckles and hubs, due to time constraints, lack of proper paint, and reminding myself that it doesn't really matter if my knuckles are painted or not.  However, it is a bit disappointing to see the new knuckles rusting after only one rainfall.  I am sure that rust on the new hubs and shocks is not far behind!

Tk2nPf9.jpg

Thanks for the help along the way.  i will share driving impressions in a few days.

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