I would like to try installing a heavy duty rack and pinion steering unit on the front axle. Has anyone ever heard of this being done? Is there a unit out there with enough strength to be used this way? Any comments or suggestions about this idea? TIA for your input.:idea:
rack and pinions aren't used with solid axles because they cause bumpsteer in that application. They are only commonly used with IFS.
If you mount it to the body, you will get bumpsteer. The only way to eliminate bumpsteer would be to mount it to the axle. If you mount it to the axle, the steering linkage gets really interesting.
Yea, skip the Rack and pinion idea. Ide go with a nice hydro assist. Find whats causing your bumpsteer...it can almost always be fixed, without redoing the ENTIRE steering system. Do you run a drop pitman arm? If you do, maybe you dont need it. theres a lot of variables that can give you bumpsteer.
Putting some thought into it, you would have to run a short track bar at each end of the axle parallel to the steering links to prevent bumpsteer. Because they would be opposed to each other, you would not be able to have any suspension travel.
The only way I can think of to make it work would be to get the rack of one of the new chevy trucks and mount it to the axle. Control it with a hydraulic motor on the rack connected to an orbital valve on the steering column. Being as there would be no solid steering linkage, it would not be street legal.
Another option would be to make the axle hinged and pivot in the middle, like a Ford twin I beam.
rack and pinions aren't used with solid axles because they cause bumpsteer in that application. They are only commonly used with IFS.
If you mount it to the body, you will get bumpsteer. The only way to eliminate bumpsteer would be to mount it to the axle. If you mount it to the axle, the steering linkage gets really interesting.
Steering linkage isn't difficult if you use the right set up. I worked on race cars for the longest time and we used servos to connect to the steering and hoses from there into the rack and ps pump. If you had a heavy-duty enough rack and servo you would be alright....besides sheering the hoses.
The idea is to mount the rack and pinion unit to the axle and have a telescopic steering shaft running to the rack. There would be no possibility of bumpsteer as the rack would be on the axle. The steering forces would be confined to the axle housing eliminating problems found with steering boxes such as the frame cracking etc. I could run some steel braded fluid hoses to the rack and have good steering feel and excellent control. There would be no steering geometry changes with axle movement. My biggest concern is getting a rack and pinion unit strong enough to take some abuse. This would be done very similar to a hyd assist except that there would be a linkage to each knuckle directly from the steering rack. I'm kind of a stubborn dude and cannot leave well enough alone so I am determined to work this out. I am a helicopter mechanic, which leaves me no opportunities to modify anything so I have to modify things on my Jeep. Do you guys think this is a viable concept given that I can do the engineering myself?
The idea is to mount the rack and pinion unit to the axle and have a telescopic steering shaft running to the rack. There would be no possibility of bumpsteer as the rack would be on the axle. The steering forces would be confined to the axle housing eliminating problems found with steering boxes such as the frame cracking etc. I could run some steel braded fluid hoses to the rack and have good steering feel and excellent control. There would be no steering geometry changes with axle movement. My biggest concern is getting a rack and pinion unit strong enough to take some abuse. This would be done very similar to a hyd assist except that there would be a linkage to each knuckle directly from the steering rack. I'm kind of a stubborn dude and cannot leave well enough alone so I am determined to work this out. I am a helicopter mechanic, which leaves me no opportunities to modify anything so I have to modify things on my Jeep. Do you guys think this is a viable concept given that I can do the engineering myself?
yes tht is all correct. the tricky part (and you will see when you look in the engine compartment and try to figure it out) is the linkage from the steering wheel to the rack. with the flex available in even a stock xj makes this really tough. not impossible though. if you search there is a thread about a 2wd with a mercedes diesel swap and a rack. the rack seemed to work on the beam ok but IIRC he seriously limited flex to make it work. not really that big a deal on a 2wd commuter but not so nice on a trail rig.
I may have to use a two piece steering shaft with a bearing near the original steering box and the telescoping part from there to the rack. Sorta like a sandrail setup. This ain't gonna happen real soon as I have other priorities and I is po'.
