1998 Cherokee 4.0 Ltd - Project

[Fourpot]

14 hours ago, digger said:

I've had a look. From the manual they look very similar but yours is longer than mine!  The Yj one is handed so I guess yours is too!

Hope this helps.

Ah, thanks for your help!

[Fourpot]

Due to a faint but increasing clunk somewhere in the front end, I decided that the lower control arm bushes were the suspects, and on close inspection, bits of the rubber were starting to fall out. Once I had the arms off I could see that the steel sleeves were worn too, thankfully the bolts were all OK.  So I bought some new lower control arms. The ones on the Jeep were part of the 3" lift kit from Rough Country, who it would seem have a poor reputation for bush quality, although it's fair to say these have been on the car for over six years. So this time I've gone with some shiny adjustable ones.

 

Adjustable because.....  well, when I reduced the lift from 3" to 2", the new OME leaf springs did not have wedges under them (to restore pinion angle). That has only now set me thinking... I've reduced the lift by 30%, but the pinion angle mitigation has gone from 3 degrees on the RC ones to none on the OME ones.  So I do some digging on pinion angle and find that mine are way out front and back. As both ends have a double-cardan propshaft, the pinion angle should be 0 degrees to the propshaft. The back is 4 deg' wrong and the front is 5 deg' wrong. The loudness and throb of my exhaust has probably hidden or taken the blame for any number of vibrations, but it may well be that these bad angles are the culprits.

 

I've put the new lower arms in, setting them at the same length as the RC ones to start with. Then I have adjusted the upper arms to get the angles right, a long job of trial and error. (The bushes at the front ends of the upper arms (pressed into the axle) are looking a bit tired, so I'll replace them at some point (It's a PITA job). Of course changing front pinion angle like this also changes the caster angle. That was at 10 deg' - way too much.  My digging turns up that 5 deg' of caster is about right for Jeeps with bigger tyres - like mine. So the 5 deg' I want to take out of the pinion angle, also reduces the 10 deg' caster to 5 deg'. Perfect!

 

The rear needs wedges inserting under the leafs (leaves?), the angle is 4 deg' out, so 4 deg' wedges ordered. 

 

I also put new bushes in the drop links and gave them a new coat of enamel orange paint. It's getting very colourful around that area - various oranges, yellows, purple, black, red, blue...!

 

(Note - the third picture showing the lower arms in place, is before I adjusted the upper arms, and with the suspension hanging low)

 

Edited March 26 by Fourpot

[digger]

Hi 4Pot. I don't know whether this is of any help to you but I thought you could be interested. I see the bases of your shocks are painted black. Mine weren't until I did it to try and stop rusting and I wonder if you have or had any issues like mine below?

I fitted  OME leafs, shocks and bushes all round on my YJ as a 2 1/2"kit about 7 yrs ago . I replaced the front springs a year ago after 6 years use and about 10k miles including JOC events plus Jeep Trek.  Last Autumn I fitted an extra leaf to the rear because my loads being carried(eg bigger tent) had increased. This had little effect and I have now replaced the rears too plus the added leaf. I also replaced the bushes of course and found they were pretty worn even though I grease shackles, clean everything  etc every time I return from a jaunt.  I  have also  had a lot of issues with rusting(really deep pitting in the end) on the  OME shocks, despite my attempts to control this. After fitting the new rear springs I had a bonking noise! After some checking I concluded it was the rear shocks.  When I removed them the one was totally shot and the other wasn't even any use as a chest expander even for an old weed like me!  I'm surprised at their short lives considering the 'strength' of the brand!  I don't consider that they have had an especially hard life!

I have now replaced all shocks with Bilstein , as previous long term experience with these has been very good. The rusting won't be an issue any more as Bilstein are galvanised and obviously the ride is transformed and returned to excellent.

Edited March 26 by digger

[Fourpot]

18 hours ago, digger said:

Hi 4Pot. I don't know whether this is of any help to you but I thought you could be interested. I see the bases of your shocks are painted black. Mine weren't until I did it to try and stop rusting and I wonder if you have or had any issues like mine below?

I fitted  OME leafs, shocks and bushes all round on my YJ as a 2 1/2"kit about 7 yrs ago . I replaced the front springs a year ago after 6 years use and about 10k miles including JOC events plus Jeep Trek.  Last Autumn I fitted an extra leaf to the rear because my loads being carried(eg bigger tent) had increased. This had little effect and I have now replaced the rears too plus the added leaf. I also replaced the bushes of course and found they were pretty worn even though I grease shackles, clean everything  etc every time I return from a jaunt.  I  have also  had a lot of issues with rusting(really deep pitting in the end) on the  OME shocks, despite my attempts to control this. After fitting the new rear springs I had a bonking noise! After some checking I concluded it was the rear shocks.  When I removed them the one was totally shot and the other wasn't even any use as a chest expander even for an old weed like me!  I'm surprised at their short lives considering the 'strength' of the brand!  I don't consider that they have had an especially hard life!

I have now replaced all shocks with Bilstein , as previous long term experience with these has been very good. The rusting won't be an issue any more as Bilstein are galvanised and obviously the ride is transformed and returned to excellent.

Interesting indeed!  I painted the bottoms black because I had to prize the bar pins out as I have bar pin eliminators fitted both ends of the Jeep. The powder coating is a little weedy and it got damaged. I put OME 3" - 6" lift shocks on about four years ago and then replaced them with OME 0" -3" more recently, when I dropped the lift to 2". Thus they haven't been on long and don't get hard use. But I think I will go to Bilstein for the next set, they seem to be the benchmark for top stuff  in all aspects of motoring (had some on my 2000 Mercedes C43 and they were fantastic.)

It seems to be a theme (no science or actual research done here) that a number of 'quality' and respected brands have off-shored to China, Smittybilt (bumpers etc) being one, and although my OMEs have 'made in Australia' stamped on them, who knows where the internals were made.

Edited March 27 by Fourpot

[Fourpot]

...and my dire patch-up on the exhaust flex joint is exposed to the world!  It had blown some of the exhaust sealer out and I needed to get it patched quick. I will eventually get that bit welded in, but to get rid of that horrible pink bandage, I'll clean it all off, reseal, and use different clamps. Doesn't leak now anyway.

[digger]

To be fair to them , i wondered if 'made in oz' was the issue. I guess they don't face endless wet and worst of all salt.

The latter should be banned in my view ! 

[Fourpot]

Bought some new axle-end bushes for the upper control arms. Standard OEM things. The bolts are supposed to be 10mm. But, holy moly, are they serious?!  The sleeve is about 12mm and not even round, and has sort of rivet heads inside, so the only contact the bolt has is with these rivet heads, and then it's not exactly snug. No wonder the things wear out and clunk.

So I drilled the sleeves out to 13mm, which was the minimum needed to get a smooth bore and found a 13mm bolt (only one so I'll get some new ones)

I'll have to drill out the holes in the UCAs from whatever they are now to 13mm, but not a big job.

the third pic is the sleeve drilled. The vids and last pic show the 13mm bolt in the 13mm sleeve and the 10mm bolt in the unaltered sleeve.

 

[UKTJ]

3 hours ago, Fourpot said:

Bought some new axle-end bushes for the upper control arms. Standard OEM things. The bolts are supposed to be 10mm. But, holy moly, are they serious?!  The sleeve is about 12mm and not even round, and has sort of rivet heads inside, so the only contact the bolt has is with these rivet heads, and then it's not exactly snug. No wonder the things wear out and clunk.

So I drilled the sleeves out to 13mm, which was the minimum needed to get a smooth bore and found a 13mm bolt (only one so I'll get some new ones)

I'll have to drill out the holes in the UCAs from whatever they are now to 13mm, but not a big job.

the third pic is the sleeve drilled. The vids and last pic show the 13mm bolt in the 13mm sleeve and the 10mm bolt in the unaltered sleeve.

 

I have seen this discussed elsewhere.  My understanding is that the bushings are designed that way, it not that you have received a bad bushing.  The way it was explained to me is that it's the clamping force of the bolt that holds the sleeve tight to the control arm. If the hole is a snug fit, the bolts tend to seize up over time and the oversize sleeve with bumps is designed to prevent the bolt seizing to the sleeve.  The logic is that the size of the hole is irelevant as long as the bolt is tightened properly.

Edited March 28 by UKTJ

[digger]

That's correct. The internal metal tube is intended to be clamped solid so that it cannot revolve in order to make the rubber bush work.   If the metal tube is not clamped you will get bad wear and noise. However I always thickly fill/coat the metal tube and bolt with anti rust grease (I use 50/50 silicone /moly). Otherwise ,especially if the bolt is fairly snug in the tube, rust will invade and can make life difficult on removal.

[Fourpot]

On 28/03/2024 at 20:20, UKTJ said:

I have seen this discussed elsewhere.  My understanding is that the bushings are designed that way, it not that you have received a bad bushing.  The way it was explained to me is that it's the clamping force of the bolt that holds the sleeve tight to the control arm. If the hole is a snug fit, the bolts tend to seize up over time and the oversize sleeve with bumps is designed to prevent the bolt seizing to the sleeve.  The logic is that the size of the hole is irelevant as long as the bolt is tightened properly.

Well that makes sense, but it's the first time I've seen it in any bush ever. Not in the lower control arms, rear leaf bushes, all the polybush replacements, and all the ones on any car I've ever had. I always put in plenty of anti-seize grease to avoid the rust seizure thing. The lateral clamping of the bush by tightening the bolt and nut up welI, should avoid 'wiggle' movement. I would have thought that the rubber bush is there to absorb impact loads up the arm, not to take all the rotation due to the suspension working, espcially at higher angles of articulation? The chassis ends of my UCAs are 'jonny joints' and rotate completely freely, as would heim joints. Intriguing.

 

Edited March 30 by Fourpot

[frosty]

i agree, i have seen this in some suspension upgrade kits, where tightening up the nut /bolt prevents movement in oversize bushes, i do not like this, in my mind it is just poor engineering, it is perfectly possible to " make parts fit correctly", i am an aircraft engineer, we never put aircraft together this way. 

As said above, lots of anti seize grease and regular lubrication will prevent problems later.  

[V]

The rubber in the bushing is there as a vibration damper, it's not supposed to take rotational forces. If the centre tube is clamped tightly it will transfer rotational forces into the rubber. The adhesion of the rubber to the tube will eventually fail so that the rotational bearing surface becomes the outer surface of the tube and the previously bonded surface of the rubber. This will wallow out the rubber and cause early failure.

 

The modern bushings made with an oval split tube centre are an awful compromise for fitting 12mm, 12.7mm (1/2") diameter bolts. The split tube allow the larger 1/2" bolt to be forced through, but they rattle on 12mm bolts.

 

I have to change my front axle bushes soon, they passed the MOT last month but have been getting noisier for months. The new MOOG parts I have bought to replace them have the awful oval split tubes, whereas older MOOG design had accurately drilled tubing. I will have to use them but I am thinking about filling the gaps in the bushing around the bolt with silicone to cure for a few days before fitting the bushes in the axle.

[digger]

This is most interesting. I'm beginning to think that maybe confusion has arisen due to modern cheap manufacturing.It is not a simple as it seems.

I have just checked in three different workshop manuals including a genuine huge 1995 Chrysler XJ and YJ one. Its not actually specific in whether the central tube is solidly clamped or not. However the torques for the through bolts range from 46ftlbs up to 109 ft lbs. I believe that at these levels the centre tube is clamped solid. I am positive that they are in the YJ and many of the bushes are interchangeable according to the Chrysler manual. The manual actually states that if any movement, noise or squeaking occurs one should tighten the bolt more! The bushes in the bottom picture that 4 pot posted are what used to be called 'Silastic' bushes. With this type the flex/movement is taken up by the bush itself. The stiffer they are the harder the ride etc  Bottom bushes on shocks are similar though different but are intended to be tightened up so the centre tube is solid . This is why one is told to tighten up loosely and finally tighten with the car on its wheels ,so that the tightening does not occur in the wrong position . If that happens then over stretching of the bush occurs resulting in early failure as V says. Any contamination with normal grease etc also destroys them.

The only 'split tubes ' I have seen are where the tube  is intended to rotate within the poly prop. The split is there so that the outer face of the tube can be lubricated via a grease nipple on the end of the through bolt ie the split (presumably cheaper to make) replaces the old fashioned row of holes. Grease compatible with the relevant bush material should be used. Red, Moly(OME), or as specified. I use 50/50 Moly/Silicone on the YJ because it is highly water resistant. I suspect (because they must move quite a lot as V says) that the tubes in the blue arms in 4pot's pic are probably loose(jolly tight fit though) ,in which case their outer faces should be lubricated so they can rotate within the red bushes

In conclusion . I believe that whether the centre tube is a fixed part of the bush or loose it was designed to be  clamped solid. 

At the end of the day if the tube is intended to move on the bolt then it is not a bearing surface of any kind and would wear and rattle. The faces at the ends of the tubes are  not a bearing surface either and if movement happens then sooner or later they will wear through the frame/axle brackets because they are physically harder (or should be!)

[digger]

This link seems pretty good at supporting what both I and V are saying! 

 

Guide to wishbone bushes - Suspension, Brakes & Wheels - WSCC - Community Forum

 

 4 Pot.  If I am correct in my suspicions, then the centre tubes in the blue arm/red bushes should push out. you may have to use a drift of some kind to push them out though if you can't move them by hand.

Edited April 1 by digger

[V]

Digger's link

https://forum.wscc.co.uk/forum/topic/88643-guide-to-wishbone-bushes/

[V]

These are the joints I will be fitting in the rubber ends of my rear suspension. I don't need them in the front because I have radius arms with Johnny joints. The radius arms don't rotate the MOOG bushings.

https://www.claytonoffroad.com/news/giiro-bushing

 

[digger]

They look really excellent, over coming the various issues with different types of joint. I thought their comparison table illustrating the different types was good too.

Edited April 2 by digger

[UKTJ]

On 28/03/2024 at 16:36, Fourpot said:

Bought some new axle-end bushes for the upper control arms. Standard OEM things. The bolts are supposed to be 10mm. But, holy moly, are they serious?!  The sleeve is about 12mm and not even round, and has sort of rivet heads inside, so the only contact the bolt has is with these rivet heads, and then it's not exactly snug. No wonder the things wear out and clunk.

So I drilled the sleeves out to 13mm, which was the minimum needed to get a smooth bore and found a 13mm bolt (only one so I'll get some new ones)

I'll have to drill out the holes in the UCAs from whatever they are now to 13mm, but not a big job.

the third pic is the sleeve drilled. The vids and last pic show the 13mm bolt in the 13mm sleeve and the 10mm bolt in the unaltered sleeve.

 

IMG_2501.MOV IMG_2502.MOV

May I ask what the make and part number was of the bushings you bought (apologies if it is in post and I have missed the info)?  I have had a look on RockAuto and I am getting Moog K3128 or ACDelco 45G8088.  Did you buy either of these or something else?

[Fourpot]

On 10/04/2024 at 09:22, UKTJ said:

May I ask what the make and part number was of the bushings you bought (apologies if it is in post and I have missed the info)?  I have had a look on RockAuto and I am getting Moog K3128 or ACDelco 45G8088.  Did you buy either of these or something else?

Crown Automotive from that Jeepey in Hull. Part number 52087709. I think the same bush goes in either end of both upper and lower control arms (although the front uppers are fitted to the axle not the arm). the blurb incudes: "Interchangeable PN: 12503, 52000211, 52003636, 52003637, 52038020, 52038025, 8952003636, 8952003637, K3128" I can only see your Moog part number in that list.

Edited April 11 by Fourpot

[UKTJ]

3 hours ago, Fourpot said:

Crown Automotive from that Jeepey in Hull. Part number 52087709. I think the same bush goes in either end of both upper and lower control arms (although the front uppers are fitted to the axle not the arm). the blurb incudes: "Interchangeable PN: 12503, 52000211, 52003636, 52003637, 52038020, 52038025, 8952003636, 8952003637, K3128" I can only see your Moog part number in that list.

Many thanks for the comprehensive answer.