Heavy steering , HDJ 100 year 2000 model

[Cruisera100]

i've been here before about bad handling , but still things are not good.
HDJ 100 4,2 D, 200 k km , manual 5 speed , ahc , 275/70 16 -100% stock.
Problem : The truck will not go down the road straight , and making smale corrections at 60 mph is so heavy, you almost need 2 hands on the wheel. When she comes -she comes - be ready to counter steer! Also you feel just about everything the tires run over. On gravel it feels like a wheel or something is lose. But nothing is.
Over the years, I have replaced every ball joint , bushing (front and rear ,upper lower) , last the steering rack. The truck is tight as ever.
Toyota has had it in the shop a few times now , but they haven't been able to figure it out. They are going to do a new alignment when people get back from vacation.
I'm thinking they maybe did a bad alignment last time (to much tow in/out ?) when they replaced the rack .And that might be why it won't go straight .The caster /camber marks are in the normal range.

But why i feel every little bump/ridge in the form of a wiggle in the steering wheel, is strange . I don't feel a thing in my volvo s-80 on the same roads. The steering wheel also pulls left or right on most roads that are not perfect. very neutral / unstable - if you know what I mean.
Could the power steering pump be bad ? Low pressure ? Standing still, lock to lock ,it is a bit heavier than a 2011 120 LC i tried. The power I do have is smooth/ constant , no pump noise or leaks. Going slow or fast the whole steering has a rubber feel to it - like the steering wheel want to go back a little ,when letting off the pressure.
Other than this , Its a great Truck ! Thanks for any help here .

 

[duggy]

Is this an IFS 100? It sounds like something is binding up. Checking your steering shaft to see if it's binding up.

 

[Spike555]

U-joint on the steering shaft is bad.
Follow the steering shaft through the firewall to the steering box/rack and pinion, there will be a u-joint, it is bad and binding up, just like bad u-joints on a driveshaft.
Have it replaced. Problem solved. I've had this on my work van more than once.

 

[bjarnep]

Maybe it is stuck with locked CDL?

 

[badlander]

Maybe a dumb question but are you sure the power steering is working correctly? Sounds like low pressure.....

 

[PADDO]

i've been here before about bad handling , but still things are not good.
HDJ 100 4,2 D, 200 k km , manual 5 speed , ahc , 275/70 16 -100% stock.
Problem : The truck will not go down the road straight , and making smale corrections at 60 mph is so heavy, you almost need 2 hands on the wheel. When she comes -she comes - be ready to counter steer! Also you feel just about everything the tires run over. On gravel it feels like a wheel or something is lose. But nothing is.
Over the years, I have replaced every ball joint , bushing (front and rear ,upper lower) , last the steering rack. The truck is tight as ever.
Toyota has had it in the shop a few times now , but they haven't been able to figure it out. They are going to do a new alignment when people get back from vacation.
I'm thinking they maybe did a bad alignment last time (to much tow in/out ?) when they replaced the rack .And that might be why it won't go straight .The caster /camber marks are in the normal range.

But why i feel every little bump/ridge in the form of a wiggle in the steering wheel, is strange . I don't feel a thing in my volvo s-80 on the same roads. The steering wheel also pulls left or right on most roads that are not perfect. very neutral / unstable - if you know what I mean.
Could the power steering pump be bad ? Low pressure ? Standing still, lock to lock ,it is a bit heavier than a 2011 120 LC i tried. The power I do have is smooth/ constant , no pump noise or leaks. Going slow or fast the whole steering has a rubber feel to it - like the steering wheel want to go back a little ,when letting off the pressure.
Other than this , Its a great Truck ! Thanks for any help here .

Did you ever reset your front height and correct your neutral pressures? Looking back at one of your Sep 14 threads your front height was too high and your pressures v torsion bar loading would have been way off as you were cranking TBs to change overall front height (not applicable for AHC). I'd be interested to see how your AHC is functioning whilst you're underway, you can monitor and record the systems height feedback and damping responses via Techstream.

 

[Cruisera100]

Thanks for all the replys.
Normaly , I do my own work on the truck . That way i know what has been done, how it's been done, and maybe find something else that needs a fix. But I let Toyota change the rack because of time , they have a lift and an alignment + it was in the shop for some bodywork. I dare say I know more about the 100 than they do , and they know it. Now that it's been there, and the bill is paid , I have some pressure on them to get this problem fixed, But they seem to need a little help , and so do I ! . Got to work while the iron is hot !
They asked for new tires - they got it - still not good.
I asked them to check the steering rack pressure , before replacing the rack, but they have not done this. If anyone knows the procedure and pressures , please let me know. Next time its in there (aug 5) , I'll be there .
I have always thought this truck could be better , because Toyota would not let something like this out on the road , and not may others complain about this problem. It is tight as ever ,but handles like crap , and you feel everything through the steering wheel

Yes ,it has IFS , and I have replaced globes , fluids and front "shocks". I have played around with heights , to see if i could make it more stable , and yes , the front likes to be lower than the rear . it is set at the Toyota recommendation now .The whole system (AHC) seems stable . But i will give it another check after Toyota is done.
I use the CDL once in a while , so it gets used a little . i know what it feels like ,I don't think its binding.
I have changed the power steering fluid , and tried the steering with the wheels in the air. it's nice and easy ,without power , and i Don't feel any binding in the steering when i do that. When they changed the rack , I asked that they make sure the U joints on the steering shaft where checked and ok , and afterwords they say that they where ok. I guess it will come of easy now ,if i want to check .
I also replaced the control valve spring in the steering pump -hoping for more pressure - and less "feel" in the steering wheel. No difference

As I said , it might have a bad alignment (I wasn't there ). I think it handles worse at speed than before the rack change .
But I am still puzzled by why I get this wiggling in the steering wheel on uneven surfaces ? Do you guys have this ?

 

[Spike555]

Check the tire pressure. If it's to high you'll feel every ant you run over.
If they put different tires than what it had before that'll make some difference, especially if it had passenger tires on it and they put light truck tires on it because those are stiffer sidewalls so they don't flex and absorb the bumps, it all travels through the suspension and steering.

 

[Live to Ski]

Same problem here.

Unclear from above, but did you do the steering U-joint check/replace?

 

[Cruisera100]

The tires are Michelin truck tires Highway/road. I forget the model, the ones that i took off where Yokohama geolander road tires. i will try adjusting the pressure. I have tried at least 3 different tires and rims 275/75 16, and some 275/?? 20. All road tires. never tried AT or mud . But the feel/problem of the truck has been the same. 265/75 16 are better (snow tires) , but the problem is still there.
The steering u joints have been checked for PLAY by me. But I did not personally check for Binding when the rack was off ,since I didn't do the job. I asked Toyota to do that .I assume they have , and they say they have . I have checked for binding with the front wheels jacked up off the ground. I could feel any binding. It dosen't feel like there is any binding -anywhere.
A good way to describe feeling in steering wheel : rolling down a hill in a straight line with the engine off - , no power assist. if the road is a little uneven , you feel a lot going on in the steering wheel . It's sort of the same thing.

 

[Live to Ski]

Feel your pain.

Will follow the thread as well as post any findings I discover. Warning.....I move slowwwwwwww (just like I drive!).

 

[Julian Stead]

What I would do is to jack the front up off the floor and see if the steering is stiff without weight and motor turned off, also there is a filter in the PAS reservoir, check that for blockage/debris. Check for bent pipework or colapsed hoses. The shimmering of the steering could be a combination of wear items, I found rear upper control arms and motor mounts gave me the most improvement in cancelling out road imperfections, this is if your AHC and tire pressures are good.

 

[Cruisera100]

What I would do is to jack the front up off the floor and see if the steering is stiff without weight and motor turned off, also there is a filter in the PAS reservoir, check that for blockage/debris. Check for bent pipework or colapsed hoses. The shimmering of the steering could be a combination of wear items, I found rear upper control arms and motor mounts gave me the most improvement in cancelling out road imperfections, this is if your AHC and tire pressures are good.

I'm not sure if there is a Filter in the PAS reservoir . But I'll take a look. I've done the other items on the list. Replacing the front UCA did make a big difference on mine too, so I replaced all the bushings and balljoints. I don't see how bad motor mounts could have anything to do with this problem
I noticed that the steering wheel / rack is way off center. Lock to lock - It goes 2.1 turns left and 1.6 right. or something like that. this will upset the AHC. So Toyota has some issues to take care of.

 

[PADDO]

What is your steering angle sensor reading and did you hook up Techstream and monitor while driving? If your SAS is providing bad data it's possible your gate valves are closed, thereby isolating each corners' suspension and stiffening the ride. They should only close whilst cornering, based on steering angle and vehicle speed.
If your power steering reservoir is the same as mine then it has a filter screen layer molded in between the return and suction ports.

 

[Cruisera100]

Paddo , Thats what I was thinking to (steering angel sensor ). I never did get my Tecstream working . I have a buddy that runs a shop with a pro monitor, But I don't want to bug him with this yet. Toyota charges over $ 200 an hour , and they have done the job , they better get it right. Next time I'm going to be there to make sure . I think the 4.2 d has a different pump and resovar , but I'll have a look. If the screen is cloged, what kind of symptoms would I have ?

 

[PADDO]

Have Toyota connect their tester/Techstream and observe your front and rear pressures after raising to N. I would also ride along during a test drive. You'll want to observe SLFG (solenoid Front Gate) and SLRG (.. Rear Gate) change from OFF to ON as a function of steering angle input. I've previously posted my observations of how the gate valves respond to steering and speed, should come up in a search. It would be worth observing whilst driving that your heights remain stable and correlate with your static heights and that your damping values (step fields) change in response to the comfort switch. In the mid comfort position on a smooth road you can expect them to vary between 2-5. They stay at 8 when not moving, and the gate valves also won't change whilst parked. Have to check whilst underway.

A blocked filter screen in the power steering pump would cause the pump to strain, potentially cavitate and make complaining noises in response to a steering input. In the petrol versions the screen has a lot of surface area and it would take a lot of debris to block it to the point it affected the steering imo.

 

[Cruisera100]

OK. just checked tire preussures ,and I see both the new front tires already have wear on the inside. They have only been on for a few hundred miles. . The caster /camber marks are pretty much in the center. Now I sure they did a (very) bad alignment. It has never worn tires uneven before.
I'll have to read up on the SLFG. SLRG
There is not , and has never been, a very bid difference in the comfort settings on this truck . But I don't really know what to expect.
The steering pump dosen't make any strange noises , and is very smooth , but kind of heavy compared to other cars (non LC) It feels a bit weak on bumpy roads - lots of feedback in the steering wheel

 

[Cruisera100]

It's my big day at Toyota on friday, So I thought I'd put on my old red Toyota mechanic dress and try and help them out. new alignment and fix these other issues. The steering rack is not in the center and i doubt the SAS is either. Can they adjust ( zero ed ) the SAS electronically or does the steering wheel/shaft have to be in a certain position ?

 

[Live to Ski]

Updates?

 

[Cruisera100]

Well , I spent half a day at toyota going thru the - ride height , Ahc pressure and a new allingment. I think Toyota liked having me there , cause they had not done the AHC stuff before.. I also changed the power steering pump - that didn't do much - if anything. A good sett up of AHC/ alignment is a must. But I still wasn't happy. The BIG difference was putting on new tires. instead of the 275/70's , that Toyota insists are the correct size , I put on 265/75 BF Goodrich AT. It transformed the truck . If I had done that right away , I might have saved myself a lot trouble.
The roads over here tend to get worn , with dips / tire track wear . Wider tires make this truck go all over the place . It's a dream to drive compared the way it was with the 275's (yokohama and michelin) road tires. I can still feel things in the road, but it dosen't take control of the car , I think nothing of it anymore. The AT's don't make anymore noise than anything else I have had , they look right , I have nothing bad to say about them ! Good luck