Power Steering Issues (1 Viewer)

[johnny decaf]

This summer my power steering pump failed while I was wheeling in the heavy sugar sand in the Jersey Pine Barrens. The initial failure was in the gasket at the rear of the PSP and happened at the same time I broke my driver side front axle. After finally getting a new axle installed I replaced the PSP with a chinesium PSP which continued to have problems. Finally last week I replaced the high pressure lines and the PSP with OEM toyota parts but I am still having major issues. Initially the power steering worked fine and felt like it just had a little bit of air left in the system. As the week went on the assist would seem to cut in and out based off of RPMS. If i got over 2600 the assist worked fine but anything under that and it was gone. Now after a week of daily driving the power steering assist has gone completely. The weird thing is that there are no leaks in the system. I have meticulously checked every single fitting and the reservoir levels every day and there are no leaks. When I start the truck with the reservoir cover off I can see fluid moving around in the res.

I am now stumped. The only piece of the power steering puzzle that is original to the vehicle is the gear box, but why would it function just fine initially and then gradually fail when there is no leak? I am not hearing any noise that would indicate I F'ed up the axle install and the truck does turn just fine when the PS system works.

I would like to add that all gaskets, O rings and crush washers have all been replaced with OEM toyota factory parts or their supplanted parts.

Thanks in advance!

 

[Fj80oregon]

Did you get all the air out of the system?

 

[johnny decaf]

Did you get all the air out of the system?

I bled it using the methods described in Romer's post. First filling the res while the high pressure hose was off, then steering from lock to lock while the front tires were off the ground and the key in the run position with engine off. Did that every hour for a half a day until I no longer saw air bubbles. Is there a surefire way to know that all the air is out?

 

[BILT4ME]

This summer my power steering pump failed while I was wheeling in the heavy sugar sand in the Jersey Pine Barrens. The initial failure was in the gasket at the rear of the PSP and happened at the same time I broke my driver side front axle. After finally getting a new axle installed I replaced the PSP with a chinesium PSP which continued to have problems. Finally last week I replaced the high pressure lines and the PSP with OEM toyota parts but I am still having major issues. Initially the power steering worked fine and felt like it just had a little bit of air left in the system. As the week went on the assist would seem to cut in and out based off of RPMS. If i got over 2600 the assist worked fine but anything under that and it was gone. Now after a week of daily driving the power steering assist has gone completely. The weird thing is that there are no leaks in the system. I have meticulously checked every single fitting and the reservoir levels every day and there are no leaks. When I start the truck with the reservoir cover off I can see fluid moving around in the res.

I am now stumped. The only piece of the power steering puzzle that is original to the vehicle is the gear box, but why would it function just fine initially and then gradually fail when there is no leak? I am not hearing any noise that would indicate I F'ed up the axle install and the truck does turn just fine when the PS system works.

I would like to add that all gaskets, O rings and crush washers have all been replaced with OEM toyota factory parts or their supplanted parts.

Thanks in advance!

What year and model is your truck?

 

[johnny decaf]

What year and model is your truck?

96 fzj80

 

[jonheld]

I bled it using the methods described in Romer's post. First filling the res while the high pressure hose was off, then steering from lock to lock while the front tires were off the ground and the key in the run position with engine off. Did that every hour for a half a day until I no longer saw air bubbles. Is there a surefire way to know that all the air is out?

The power steering system self bleeds. There is no need for all this nonsense to bleed the PS system.
Engine off. Fill the reservoir and put the cap back on or you'll just make a mess. Start the engine for a second or 2 and shut down. Refill the reservoir to the proper level. Repeat until the level in the reservoir no longer drops. With the engine running, turn left/right a few times and recheck the level in the reservoir. Done.

If there's no air in the system, then I would blame the unknown PS pump.

 

[BILT4ME]

96 fzj80

What are you using for power steering fluid?

 

[johnny decaf]

The power steering system self bleeds. There is no need for all this nonsense to bleed the PS system.
Engine off. Fill the reservoir and put the cap back on or you'll just make a mess. Start the engine for a second or 2 and shut down. Refill the reservoir to the proper level. Repeat until the level in the reservoir no longer drops. With the engine running, turn left/right a few times and recheck the level in the reservoir. Done.

If there's no air in the system, then I would blame the unknown PS

This is the second pump to behave this way though. First it was the Chinese one so I mustered up and bought the brand new Toyota pump and it’s behaving nearly the exact same.

 

[johnny decaf]

What are you using for power steering fluid?

ATF 3

 

[jonheld]

This is the second pump to behave this way though. First it was the Chinese one so I mustered up and bought the brand new Toyota pump and it’s behaving nearly the exact same.

Are you getting foam in the reservoir after driving?

 

[smritte]

Did you replace the low pressure hoses. You said high pressure, just checking. If not, a hardened suction hose can pull air past a tight clamp. I have seen this many times over the years where people just replace the pressure side. Pretty much anything on the pump suction side can cause what you describe.

 

[BILT4ME]

Did you replace the low pressure hoses. You said high pressure, just checking. If not, a hardened suction hose can pull air past a tight clamp. I have seen this many times over the years where people just replace the pressure side. Pretty much anything on the pump suction side can cause what you describe.

This also makes me think of the reservoir. Mine leaks a tiny bit around the bottom tube and a lot from the top lid of the reservoir. I bought a new reservoir, I just have not installed it yet.

Oh, and get a new reservoir cap while you're there. The seal on it is hard as a rock by now.

 

[80serie]

If you changed the high pressure line, maybe there was pieces of rubber in the line resulting from the crimping of the flexible line. These FODs made there way to the gear box and clogged the hydro passages. It happened to me twice! Your pump may be good but your problem is further down the line in your gear box. Here is a picture of what it looked on my truck. That being said, it is not costly if you do the job yourself, it’s 2 days of work and messy!

 

[johnny decaf]

If you changed the high pressure line, maybe there was pieces of rubber in the line resulting from the crimping of the flexible line. These FODs made there way to the gear box and clogged the hydro passages. It happened to me twice! Your pump may be good but your problem is further down the line in your gear box. Here is a picture of what it looked on my truck. That being said, it is not costly if you do the job yourself, it’s 2 days of work and messy!
View attachment 3474749View attachment 3474750

I’ve got a feeling this is the issue. Is there a walkthrough that you followed for cleaning out the gearbox?

 

[johnny decaf]

Did you replace the low pressure hoses. You said high pressure, just checking. If not, a hardened suction hose can pull air past a tight clamp. I have seen this many times over the years where people just replace the pressure side. Pretty much anything on the pump suction side can cause what you describe.

I have replaced all but one of the low pressure hoses so I’ll get in there and replace the last 3/8 one this weekend.

 

[80serie]

I’ve got a feeling this is the issue. Is there a walkthrough that you followed for cleaning out the gearbox?

Steering gear box rebuild

This is the second time I’ve seen the inside of an 80 series gearbox. I bought a used box this summer and rebuilt it with the help of a good friend and Lexus mechanic. Then we swapped it onto the truck in place of the original box, which was leaking from the input seal. Unfortunately, I managed...

forum.ih8mud.com

Here is the thread I followed. The step by step and the according pictures are very well explained. This guy did a very good job. Pay extra attention when removing the power piston plunger guide nut. I had to remove it with a chisel and weld a bolt head afterward… naturally I had to file back by hand all the remaining threads. You will have to go one step further and remove the snap ring to check the input shaft. But it is not a big deal as you can see on the picture I sent you. Be sure to run compressed air in all the passages to clean everything. Reassembly is pretty straightforward if you follow the step by step. Finally when reinstalling the high pressure line, I found it easier to install first the end at the box before the end at the pump. Don’t rush the job, take your time to check every détails as you go along and it will be fine.
Feel to ask any question if something needs to be clarified.
Picture below is the salvaged plunger guide nut.
Cheers