Do I Need an Adjustable Panhard Rod? - Land Rover Forums : Land Rover and Range Rover Forum

troverman2 · 12-07-2012, 12:44 PM

OK, so I only have a 2" spring lift plus a 2" body lift which doesn't affect steering. But, my RRC is absolutely chewing through panhard rod bushings...but only on the frame end, not the axle end. People have said, no, you don't need it, just get OEM bushings...yeah, did that. It costs me $40 to have a shop press the old bushes out and the new ones in. The bushings are lasting me a month on average. When that bushing goes, the steering is all over the place, as you'd expect. I drive this vehicle off-road in off-camber terrain frequently, which flexes the suspension a lot. I'm suspecting this off-road use quickly wears out the bushing - but I can't figure out why its only the frame side bushing!

Will an adjustable rod solve my problem?

Thanks

ArmyRover · 12-07-2012, 02:10 PM

That is odd, is there any bends in the pan hard? Is the power steering leaking at all on the bushing?

p76rangie · 12-07-2012, 03:21 PM

Quote:

Originally Posted by troverman2

Will an adjustable rod solve my problem

No

roverandom · 12-08-2012, 09:24 AM

What sort of shape is the rest of the suspension in? Worn components can indirectly be the cause of problems all over the place.

troverman2 · 12-10-2012, 05:21 AM

Suspension is mostly all new within the last 2 years. New +2" coils, pro-comp 9000 shocks, all bushings on front and rear radius arms new, etc. Front sway bar removed. No leaks from PS pump on that bushing. Panhard rod just has the factory bend in it to clear the diff. Attached is a photo which shows my panhard rod. This problem is driving me crazy, and right now, the vehicle is basically unsafe to drive because the steering has so much wander. Of course, if I replace the bushings again, the steering will be tight...for a while...

76FJ55 · 12-10-2012, 06:22 AM

Can only think of one suggestion. As with all rubber bushing you should have them in the neutral position when tightened down to minimize the stress on the rubber. Don't know what position they are in when you install the but ideally you should have the truck with the weight bearing on the axle so the panhard is in its neutral pusition then tighten the securing bolt. If you've got the truck lifted by the frame when you tighten the bolt the inner rubber will be under stress when the truck is taken off the jacks and then under a great deal more as the suspension is compressed while driving.

troverman2 · 12-10-2012, 06:28 AM

76FJ, thanks. I don't need to jack the vehicle up to remove the panhard rod, so that shouldn't be an issue. Also, the panhard rod is designed to be able to move freely vertically but not horizontally...tightening the bolt up does not restrict vertical movement.

76FJ55 · 12-10-2012, 07:10 AM

Yeh, I knew you could get to it with it on the ground, just didn't know if you we're lifting it for convenience. As for the movement, I understand it is designed to allow vertical travel. The issue with tightening any rubber bushing without it loaded wont restrict movement. It just decreases bushing life. When you tighten a rubber bushing down you are locking the inner steel sleeve in position rotationally, and if that position is not the natural position it will set in when the suspension is loaded it increases the stress on the rubber element as it is twisted further than designed.

Presumably it is the twist that is causing the bushing to fail. You may check into a poly bushing as the inner steel isn't bonded to the poly and is designed to slip and allow independent rotation of the bushing.

troverman2 · 12-10-2012, 07:35 AM

No, the inner rubber never gets twisted. The bushing hole becomes elongated along the horizontal plane in my case. When the panhard rod is bolted to the chassis (or axle) mount the mount does not compress against the outer or inner steel sleeve. When the suspension travels, force is exerted laterally against the rubber, but the rubber is never twisted.

roverandom · 12-10-2012, 08:55 AM

Are you torquing the bolts up correctly? Can't remember the TQ setting off the top of my head but I thick it's up in the F*#@ing tight range? Obviously a under torqued nut and bolt will come loose but also a over torqued bolt set can sometimes not provide the required clamp load, especially in high stress areas like suspension components and head bolts etc. Also over/under TQ of the hardware can cause bushing deformation/movement.

I once had a problem with my panhard bar bolts coming slightly loose after bushing replacement. It would show up as a crack or snapping sound when turning at slow speed. I deduced that the hardware was no longer up to the task and replaced it and never had a problem after that.

I would try a brand new grade 8 nuts and bolts and torque to spec with a thread locker.

My 2c.

troverman2 · 12-10-2012, 09:00 AM

Everything seems to be nice and tight. I can see the month-old bushing has elongated...I can grab a tire and rock the vehicle sideways, and the chassis is not in sync with the axle / wheel...thus my problem. I guess I was just thinking putting an adjustable rod (i.e. adjusted slightly longer than the stock rod) would take the stress off the bushing.

76FJ55 · 12-10-2012, 09:30 AM

Is the inside of the panhard bar mount worn from movement of the inner steel bushing? When tightened correctly with all conponents in good condition, the inner steel sleeve should be captured and have no relative movement between it and the mount. All motion should be handled in the twist and compression of the rubber. If you are getting elongation of the hole in the inner steel sleeve it is not captured correctly. Either the bolt hasn't or can't supply enough clamping force or the inside of the mount is excessively worn.

troverman2 · 12-10-2012, 11:22 AM

If I'm understanding correctly, you're talking about the panhard rod and not the chassis mount itself? If yes, it is not worn (obviously still needing to be pressed in with a shop press). I believe everything is in its proper form with no wear occurring to anything except the bushing is wearing out. I'll look at it again tonight and try to make some sense of it based on the advice here...

76FJ55 · 12-10-2012, 12:15 PM

the rubber bushing should have both an inner steel sleeve and an outer steel sleeve. the outer steel sleeve should be a press fit into the panhard rod. once installed into the panhard rod there should be no relative movement between the outer steel sleeve and the panhard rod. Likewise with the inner steel sleeve once installed and torqued the propper installation should make the inner sleeve "become one" with its respective mount. there should be no relative movement between the inner steel sleeve and the frame mount or associated bolt. All rotational movement alowing for axle vertical movement is supposed to be handled by the tortional deflection of the rubber bushing. if the inner steel sleeve is rotating with the rotation of the panhard rod the installation is not correct. so if you are seing elongating of the inside of the inner steel sleeve it indicates that the inner sleeve is moving with the panhard rod and being hammered out of shape on the mounting bolt, which verifies thath the install is not securing it correctly.

Can you post a picture of one of the failed bushings? If so it may help in diagnosing the cause of the failure.

troverman2 · 12-10-2012, 12:20 PM

I'll try to post a pic soon. I understand what you're saying. However, my understanding of how it works on the Range Rover is that the bolt rotates within the inner steel sleeve, allowing the vertical movement. The design of the mount (large, flat steel sides) force the mount to come into contact with the panhard rod itself before tightening down and "becoming one" with the inner steel sleeve. I'll try and get some pics, and I appreciate your help here.