Hard steering rd688sx

[TrashMan08]

New to site need some direction. 1996 e7 350. A million mile rolloff. Stiff steering left and right, cold or hot. I mean two hand pull. King pins tolerance seem ok changed fluid, filter lubed everything twice. Just some thoughts toward first steps. Thanks for any help. Mack wants 1k for new pump.  Get site read almost daily.

[theakerstwo]

When you apply the brakes it makes the power steering work harder as you turn the wheels from stop to stop.

[theakerstwo]

First of all you need to find out whats the problem before you start buying parts.You need some gauges on the system to check the floe and pressure.You can use a 3000 psi pressure gauge and tee in to the suppy line to the steer box.With the engine running maybe 1500 turn the wheel and watch the pressure.You can check this out your self if you understand the system.To check the max pump pressure hold the brakes down and take a reading.You need to see 1500 or better with brakes applied.

Edited November 10, 2019 by theakerstwo

[terry]

52 minutes ago, theakerstwo said:

First of all you need to find out whats the problem before you start buying parts.You need some gauges on the system to check the floe and pressure.You can use a 3000 psi pressure gauge and tee in to the suppy line to the steer box.With the engine running maybe 1500 turn the wheel and watch to pressure.You can check this out your self if you understand the system.To check the max pump pressure hold the brakes down and take a reading.You need to see 1500 or better with brakes applied.

Guess I missed something here, what does brakes have to do with power steering pressure?    terry

[TrashMan08]

Brakes not part of system but will def start with pressure readings. Thank you for help i feel like popeye. Don't know whats worse, 1k pump or kingpins.

[TrashMan08]

You know, was just thinking maybe you mean more stress on steering when trying to turn wheels. Thanks learned something new.

[theakerstwo]

Another way to read your max pump pressure is put aa wooden block between aa wheel and the frame and try to turn with hi rpm.

[FBGNO]

Don't think that I'm crazy, but I had one driving me crazy, checked the pressure and pressure was low, changed the box great pressure, same exact problem, I disconnected the steering column and all was fine. The problem was the bearing on top of the housing for the double u-joints. The truck was a bear to steer, I changed that bearing and you could steer the truck with one finger. Now it is a must for any truck that comes into the shop for a service, that bearing gets oiled as part of the service. 

[TrashMan08]

Thanks FBGNO going to check asap. Running truck this week and steering gets better after few hours!?!?!. going to check pressure this weekend and replace some lines to box. Thanks again helpful info.

[Swishy]

If all else fails

Jack the front end up n get sum daylight under the wheels turn steering full lock 

grease king pin turn on oposite lock & grease again

center steering & gently lower to ground

this method gets grease to the load side of the axle K/Pin

cya

 

[terry]

3 hours ago, Swishy said:

If all else fails

Jack the front end up n get sum daylight under the wheels turn steering full lock 

grease king pin turn on oposite lock & grease again

center steering & gently lower to ground

this method gets grease to the load side of the axle K/Pin

cya

 

Also gets grease in the bearing on bottom of kingpin.    terry

[david wild]

Bigger arms  ????

[JoeH]

46 minutes ago, david wild said:

Bigger arms  ????

Put a fuller transmission in it!!!!

[david wild]

gettin lazy maybe a Auto ????

[TrashMan08]

Thanks to all, i will go and do a wheel stand and loaded it with grease, and eat more spinach. Got pressure gauge in mail today going see what she has to tell me. Auto steering? David Wild sounds fun sign me up.

[mechohaulic]

did  you start with simple process of elimination  when fluid was changed ; meaning pull hyd lines off blow air through lines , make sure opposite end is in a pail or gallon jug ;  see if inner lining has folded over and blocking line? or maybe some one crossed lines. have even seen dry  grease/ dirt packed between spindle and axle make a difference. pressure wash …   pull filter cover; remove filter:   COVER with clean rag and start unit. should see  oil flow  fountain into canister.  DON"T race engine at first  oil will be all over . does it have single or dual steeringboxes ?  how does it drive going down the road ????  tires wearing smooth ?? front end out of toe will make a difference.  remember i'm not use to these "new" trucks LOL . throwing out ideas based on past experience  

[TrashMan08]

Thanks so much for your help. Tires where wearing funny too. i did look at hoses some need replacing. After closer inspection someone redid king pins and did not install correctly. The adjusting nut was not set right and axle was riding on spindle not bearing. I guess easy mistake diff from other king pins this truck has tapered pins. Axle rides on bearing only.  Bought new king pins set from mack at reinstalled new set. Old bearings where chewed up. Was easiest king pins i have ever done. love these old macks two hits pin shoot out. one day both sides. Turns like grandmas lincoln town car now. Thanks to all