Swapping to rack and pinion/ building a simple mid-travel kit

[Burdom13]

Ok. I know this has been spoken about but I've yet to see anyone complete this task. I'm going to be switching out the stock steering to a gmt800 Silverado rack and pinion. I've used em on my 99-07 2wd Long Travel kits with 37s and rarely had issues. (Proper geometry and limiting binding issues helps longer life)
So what Im planning on doing is TRYING to offer a bolt-on kit, but I'm pretty sure some minor fabrication and welding will be required. QUESTION: will my stock p/s pump work? I know there will be line fittings/adapters needed. And YES I know about the bump steer and geometry changes. My goal is to basically make a simple conversion kit cuz the steering geometry sucks ass once you lift these trucks. SUSPENSION: gonna try to figure out a uniball upper arm to make the spindle height a tad taller and maybe relocate/modify UCA pivot points to help with camber and caster curve through travel. I've built plenty of newer Silverado LT kits as well as other vehicles too. I just can't seem to find **** for these trucks. Possibly cuz torsion bars suck ass too. Anyone possibly interested in this type of suspension kit? And anyone seen/have pics/link to the rack and pinion conversion???

 

[yevgenievich]

Going away from torsion bars would be my guess on getting it to work. There is a rack and pinion kit for 2wd. On 4wd seem most logical way for larger tires or travel is sas

 

[Burdom13]

So...SAS is a hell of a lot of work. If I was going that route I'd def do that or do full LT kit. Just trying to build a nice simple kit that adds some wheel travel and fixes the issues when lifting these trucks. Then I'll be adding a coilover option to the kit too. But she to welding/cutting most people can't do this. But I'll begin to post pics once I start the build. Probably doing the steering swap first. That way I can already have the new steering geometry figured out

 

[98yukon]

While I don't have the numbers in front of me, I'd be a little worried about using the factory pump for a rack and pinion. Unfortunately I'm having a difficult time finding an operating pressure for the GMT800 rack so I can't tell you for sure, but I'd be willing to bet that your pump outputs a higher pressure than is needed for the rack, and possibly more than it can handle. Do you know what kind of pressure you're looking for?

The pumps put out ~1200psi to drive the gear (not accounting for EVO), which is likely more than you'll need for a rack - and may blow it apart. This is frequently an issue for old hotrodders switching to Mustang II suspension, the Saginaw pumps will blow up a MII/T-bird/Fox rack if you don't bring the pressure down to 750-800psi. There are companies out there that sell valves to regulate the pressure from a pump originally designed to drive gear and make it safe for racks. It bridges the pressure and return lines to bleed off some of the pressure directly into the return, and depending on who you get it from can be adjustable and could include a gauge so you know you're operating a safe pressure.

 

[Burdom13]

While I don't have the numbers in front of me, I'd be a little worried about using the factory pump for a rack and pinion. Unfortunately I'm having a difficult time finding an operating pressure for the GMT800 rack so I can't tell you for sure, but I'd be willing to bet that your pump outputs a higher pressure than is needed for the rack, and possibly more than it can handle. Do you know what kind of pressure you're looking for?

The pumps put out ~1200psi to drive the gear (not accounting for EVO), which is likely more than you'll need for a rack - and may blow it apart. This is frequently an issue for old hotrodders switching to Mustang II suspension, the Saginaw pumps will blow up a MII/T-bird/Fox rack if you don't bring the pressure down to 750-800psi. There are companies out there that sell valves to regulate the pressure from a pump originally designed to drive gear and make it safe for racks. It bridges the pressure and return lines to bleed off some of the pressure directly into the return, and depending on who you get it from can be adjustable and could include a gauge so you know you're operating a safe pressure.

I totally forgot I made this thread lol. Thank you for the info. This is exactly what I'm needing to figure this out. What about if I put a pump from a 5.3L on?

 

[Burdom13]

So i havent posted on this yet but ihave some info for anyone interested in a kit like this:

I am running coilovers and switching to rack and pinion and have also found that the cvs from a 09-13 silverado are 1 15/16" longer per side than the 88-98 gmt400 or gmt800....that being said, i am gonna run the high-articulation cv axles from napa for the 2009-2013 silvy, and i am building new upper and lower control arms that are 2" wider per side and move the tire forward 1.5" for firewall clearance. depending on how well the new brake calipers i got from stoptech work, i may or maynot build new spindles to utilize the gmt800 calipers. unless there is a way to make an adapter bracket for the gmt400 spindle to use the gmt800 calipers? curous if the rotor is wider or the same width for both? on another note: i dont like the bushwacker fenders cuz of the pocket rivets, and the bigger they go the fnuuier they look, and i havent found any fiberglass fenders im a big fan of, so i making my own out of steel lol. trying something different since i have an english wheel and shrinker/stretcher to make the edge lip of the fender openings. i know this is a lot of work but i havent found anyone that is doing something like this.....and i have done MAJOR RESEARCH. i know there have been the tahoe builds but seriously havent found a gmt400 pickup that had a similar idea like im doing. and i want to get this to work before i do a SAS. just want to be different cuz independant suspension can be so dialed!!!!

 

[Alteca]

So i havent posted on this yet but ihave some info for anyone interested in a kit like this:

I am running coilovers and switching to rack and pinion and have also found that the cvs from a 09-13 silverado are 1 15/16" longer per side than the 88-98 gmt400 or gmt800....that being said, i am gonna run the high-articulation cv axles from napa for the 2009-2013 silvy, and i am building new upper and lower control arms that are 2" wider per side and move the tire forward 1.5" for firewall clearance. depending on how well the new brake calipers i got from stoptech work, i may or maynot build new spindles to utilize the gmt800 calipers. unless there is a way to make an adapter bracket for the gmt400 spindle to use the gmt800 calipers? curous if the rotor is wider or the same width for both? on another note: i dont like the bushwacker fenders cuz of the pocket rivets, and the bigger they go the fnuuier they look, and i havent found any fiberglass fenders im a big fan of, so i making my own out of steel lol. trying something different since i have an english wheel and shrinker/stretcher to make the edge lip of the fender openings. i know this is a lot of work but i havent found anyone that is doing something like this.....and i have done MAJOR RESEARCH. i know there have been the tahoe builds but seriously havent found a gmt400 pickup that had a similar idea like im doing. and i want to get this to work before i do a SAS. just want to be different cuz independant suspension can be so dialed!!!!

Keep us updated, I would love to see some custom fenders. I could use a set that’s about 1.5” wider on each side but don’t have the tools to make them.

 

[Burdom13]

UPDATES!!!!!!!! So finally tore the truck apart. years later, but better late and prepared, than rush mess something up!!!! im super excited to finally get this truck going. Ihave all the parts on hand, except for the cvs and fiberglass, which are ENROUTE as i type this.. So i ahve basically changed every idea i was originally going with and decided im just gonna make EVERY COMPONENT MYSELF. not doing rack and pinion as i found out the steering gearbox is always going to be stronger and when properly setup, is wayyyy stronger and you can achieve better steering geometry by mking your own centerlink. ive already started the idler arm bracket, and spindle blocks faced on the lathe and have the hub centric almost pressfit into the snout blocks. ill show some pics soon. but im running the dual piston calipers and rotors off a 2007 tahoe. found a set of near-new at the junkyard for $85, so im just building my own spindles instead of stock steering knuckles/spindles. upgrading the gearbox to the GMT800 but havent decided on which one specifically, due to this re-manned i got at o-rielys was shot out in like 2 months. so im thinking blue-top or redhead for a 99-07 GMT800 instead of the GMT400 88-98 box. unless someone has any advice? my predicament is mainly cuz i have the warranty at o'rielys and factoring in core-charge so i dont have to pay $4-500 on a quality box. ANYWAYS........so boxed uppers and lowers, possibly fully fabricated spindles(if i cannot achieve the travel numbers i want with the GMT800 spindles) 2.5x8" coilovers, fabricated pitman/idler arms and idler bracket, fabricated centerlink to put the pivot bolts in double shear, and full heimed steering. 7/8" outer and inner. 1inch uniball and 3/4" heims for upper arms, and moog balljoint for lower pivot, or 1" uniball if i cannot get the larger travel numbers, and the tru-trac extended travel cvs from a 2009 silverado since they are 2" longer than the GMT400. ive done all my research and junkyard hands on info for awhile now. i got this lol

You must be registered for see images attach

 

[Burdom13]

ALSO........plan on making fixtures for everything, and i will be able to make anything if someone wants. I also have my old torsion bars/tube uppers torsion keys and yellow bilstiens for sale

 

[revmatcher]

How's the project going? I'm thinking of doing a rack and pinion conversion on my 1997 2-Door Tahoe 4WD.