98 Yukon weird driving issue

[redchevy914x4]

I just came to be the owner of a clean 98 gmc Yukon 4 door 4x4. It has 155k miles and is all stock. It is a push button transfer case. When making a higher speed turn with the brakes applied it feels like the brake on the inside side is grabbing different than the outboard brake. So making a right turn it feels like the right side is grabbing more than the left. it does it turning both directions but does not do it all the time and the faster you are going the worse it feels. It almost pulls the steering wheel out of your hand sometimes. I checked the brakes, suspension, and steering and everything is good and tight. The brakes do feel a little mushy so I am going to try bleeding them to see if it helps any. Could it be a problem with the hydro boost system or something? Does anyone have any ideas what it could be?? Any help is greatly appreciated. Thanks in advance.

 

[df2x4]

I'd be replacing the soft lines on the front brakes before trying anything else. Odd that you're having issues on both sides at once, but my gut feeling tells me that's your problem.

 

[redchevy914x4]

Mine too. I just ordered a stainless steel brake hose kit and some nice rotors and pads. Figure it's been a while since they have been done anyways.

 

[redchevy914x4]

Come to find out after research it looks like there is something in the power steering pump called an evo? Looks like I can bypass this? The issue is actually referred to as a steering "twitch." Does anyone have any more information or know what I am talking about?

 

[Ironhead]

This is getting interesting for me as well. On low speed turns, especially to the right, it sometimes feels as though something grabs the steering wheel/tie rods, or whatever, and jerks the truck a bit. Any insight into this would be great.

 

[Ironhead]

Just found this on another site:

http://67-72chevytrucks.com/vboard/showthread.php?t=29241

And this:

http://my.cardone.com/techdocs/PT 20-0031.pdf

And this, from another site;

Anyway, the EVO is about $100Can. from the dealer and it takes about 20 minutes to install one. It looks like a really skinny black doughnut about 3 inches in diameter and the thickness of 3 quarters. Inside the truck near the bottom of the steering shaft is a nut and bolt for you to remove. Then push the bottom part of the steering linkage into the engine area. Up the shaft you will find the EVO with 3 clips holding it in. Unplug the EVO and lift the clips with a small screwdriver to release the EVO - Don't beaks the holding clips!. Then slide the EVO down the shaft and off. Install the new EVO using reverse order of these these instructions.

 

[redchevy914x4]

Awesome!! That is exactly what my Yukon is doing.

 

[df2x4]

Alternatively, if you want to delete the EVO component of the steering system entirely you can. GM has a kit, or if you want to do it as cheaply as possible @sewlow has some great information on a DIY method. Info on both can be found in this thread, including that part number for the GM EVO delete kit.

http://www.gmt400.com/threads/replacing-power-steering-speed-sensor.31872/

I have fully functional EVO steering in both of my trucks and I don't mind it, though. Only had one sensor die in approximately 20 years between both of them.