Crown Wheel and Pinion Replacement Options??

[ricster]

Ross..... man, I'm really happy you are back in the Patrol.... what a journey....what a ride

[Tinus lotz]

Nice to hear you are on the road again ......it was a long one

[LERZ]

Ross reading this was painful But I am glad you are back on the road again.
Jacque

[Overdrive]

Ross, glad you got this fixed. Can you tell us a bit more about the vibration you had? Reason is my lorry is also developing a vibration between about 95 and 100 km/hr. Ive had the wheels balanced and aligned. Ive checked the weels for play. Nothing I can feel there. So I am puzzled and wondered if it may be a problem similar to your.

[Ross]

Thanks all for the comments.

@Overdrive: My vibration was as a result of a bent pinion gear on the rear axle, which manifest mostly on over-run for some reason. Its highly unlikely that your vibration would be from that reason, unless the rear axle has taken a serious knock.

The vibration you describe is most likely the well known Patrol "Death Wobble" (google it, or search the Aussie site...its a well known issue). If the Alignment and Balance is known to be good, you need to check the pan hard rod bushes for play (watch each end of the pan hard, while someone turns the steering wheel back and forth), if that checks out, you most likely need to either remove the King Pin Bearing Shims, or move to thinner shims. SRXy recently bought a GQ for his Father which had significant "death wobble" vibration between 80-100km/h....after removing the king pin shims, she drives perfect again!! If your Patrol has more than 160k km`s on the clock, chances are fairly good that the king pin bearings are sufficiently worn to run without shims. Removal is easy, there are 4 bolts that hold the upper and lower bearing cap on each side...simply undo the bolts, lift off the cap and remove the metal shim, and then place everything back together. Do keep the shims somewhere safe though...one day you will need to replace the king pin bearings, and new bearings will require the shims again to get the correct pre-load.

Hope that helps,

Ross

[ricster]

Rod.... is that vibration you are talking about felt on the steering. In other words, do you get a steering shake between 95 and 100, or is it more a body shake or vibration. If a body vibration then it could be a dry or worn universal joint.

I also have the steering wobble at 80-90Km/h, and will be taking out a shim on the kingpins, as I think the bearings have worn out a bit. I'll then look into replacing when I have time.

[Overdrive]

thanks Ross excellent advice. I checked the panhard bushses - no sign of movement there. I took out the shims from kingpins and Waahlaa - no more death wobble coming thro the steering wheel. Much better.

But.... there is still a general vibration coming from what feels like under the lorry and from the back but its hard to tell at about 90 to 110kph. So Cedric, I think you may be right, it may be the universal joint at the back. So next question; is there any way of testing to see if a universal joint is worn?

When I bought this lorry there was a horrible scraping noise every time I went through an axel twister. Eventually we found that the long range tank cage was scraping against the prop shaft when a real wheel was raised. Anyhow in the process of finding this problem one of the workshops loosened the gearbox mountings and shifted the gearbox a bit. I would have thought that the gearbox and the prop shaft had to be nice and straight - all lined up. Could that be the cause?

Sorry I didnt mean to hijack this thread with these different problems but who know maybe they are related somehow? Apologies.

[Clem]

Guys, I wonder about the wisdom of simply whipping the shims out - shouldn't one check the pre-load in all cases? Surely a too high pre-load is also no good?

[ricster]

Clem, yeah I think you do have a valid point regarding preload, but from what I have seen on the various forums, that shim is just sufficient to take up the slack from the wear in the bearings. I can't recall the preload tension of hand, but as a temp fix, until replacing the bearings can be done.

Rod, I think the best would be to take it to a propshaft place, but if I'm not mistaken, there are grease nipples on the UJ's. If you have a grease gun, pump some grease into each UJ, one at a time, then take a drive and see if there is an improvement. Then grease up the next one and repeat till either there is a difference ( even slight ). At the end of the day we put a LOT of torque through those UJ's from fairly powerful motors. If they haven't been replaced, it may be time to do that.

[Stefan]

Glad to hear you sorted out the problem Ross. Thanks for the invaluable feedback as well!