Advice Requested - Hydroboost Unit

[Sharecropper]

After eleven months I finally completed my powertrain swap to a point where I could take a short test drive, back & forth beside my shop building before taking it out on the road. During the engine assembly period I had rebuilt my PS pump by reconditioning my original reservoir and installing a new PSC High Performance SP1400 pump into it. I installed the completed pump onto the P400 engine with the OEM bracketry and aligned the PS pulley with the other pulleys. I re-used the original pressure lines from the pump to the Hydroboost unit because they appeared fine with only 15,178 original miles. I filled the rebuilt PS pump to the line with new Dex 3 fluid.

After confirming that all engine fluids were at correct levels, I cranked the engine several times for a short break-in period and to look for leaks. Everything looks good, so I then jacked-up the front end, cranked the engine again, and cycled the steering wheel numerous times from fully-locked left to fully-locked right & back to refill the PS lines & Hydroboost and to "burp" the system. Everything again looked, felt, and sounded good, so after refilling the fluid level one last time, I slowly pulled the truck out into the sunshine.

Back & forth I went beside my shop several times with all systems working as designed. Brought it to a stop and checked all fluids again, then repeated the back & forth drive beside my shop. I could not have been more pleased with my creation. The Supercharger was producing 3 pounds of boost at idle and the throttle response was instantaneous. The electric fans came on at 190 degrees and oil pressure was great. The steering was effortless with no slop or hesitation. I decided to drive the truck around the block.

After I had turned the first corner, suddenly I lost my power steering and power brakes! I then had to struggle to get back to the shop and get it inside, where I shut it down to figure out what just happened and what to do next. Either the new PSC power steering pump failed or the 42-year-old Hydroboost unit failed. And I would guess the chances are the Hydroboost unit is the culprit.

So I thought I would post on here to ask for opinions of what to do next. I suppose I should somehow check to make sure the PS pump is indeed pumping properly, and if it is, then confirm that the Hydroboost unit has failed. And if this turns out to be the case, I will have to decide whether to install a rebuilt Chinese Hydroboost unit or try to find somebody or a shop to rebuild my unit.

Thoughts anyone? Thanks in advance for your help.

 

[Barrman]

Very happy to read your engine is doing what you envisioned! That is great.

To have a sudden loss of both boost systems to me says fluid loss, belts slipping or the pump is the issue. I just looked in the -20 troubleshooting section and it doesn’t help any. The -34 troubleshooting section is perfect for this. It gives psi readings and flow rate specs for the pump. The power steering pump control valve comes up a good bit. That leads me to suggest rigging up a way to test output of the pump. Then probably pulling the pump assembly to look inside. Not knocking your work but you did have the pump apart and things do happen and bad parts seems to happen a lot these days.

 

[Sharecropper]

Very happy to read your engine is doing what you envisioned! That is great.

To have a sudden loss of both boost systems to me says fluid loss, belts slipping or the pump is the issue. I just looked in the -20 troubleshooting section and it doesn’t help any. The -34 troubleshooting section is perfect for this. It gives psi readings and flow rate specs for the pump. The power steering pump control valve comes up a good bit. That leads me to suggest rigging up a way to test output of the pump. Then probably pulling the pump assembly to look inside. Not knocking your work but you did have the pump apart and things do happen and bad parts seems to happen a lot these days.

Thanks Barrman. I can confirm that there are no belts slipping and the fluid level in the pump reservoir is correct, so the issue must be either the new PSC pump is not pumping or the Hydroboost has failed. Where in the -34 did you find the section about troubleshooting? I'm in there now and can't seem to find the page.

 

[Skinny]

Seems like no matter how many times I replace a box the pump immediately fails after or vice versa.

So my first immediate recommendation is DO NOT buy anything from Sweeting Performance. When people search br perfectly clear he is a crook and you'll have enough reading to make this abundantly clear. Ask me how I know.

You can buy new Bosch boosters and there are plenty of vendors that sell them with the firewall a plate to bolt up to a square body for $650-750.

 

[Barrman]

TM 9-2320-289-34. Pages 2-27, 2-28 and 2-29.

 

[sbgarage]

There one on eBay for $89 plus shipping search cucv hydro boost, not affiliated with seller, ymmv

 

[WWRD99]

Since you lost brakes and power steering it's the pump. Just because it's new doesn't mean it's working. Could pull the return off the steering box and see how much fluid comes out. Need a long hose and a milk jug. Turn the wheel some and see if anything comes out.

Sent from my SM-S906U using Tapatalk

 

[Sharecropper]

Well, it's the pump. In fact, it's the new PSC SP1400 High Performance pump which lasted all of 20 minutes of driving. And because it has been eight years since I purchased the pump, obviously PSC will not honor the warranty. PSC wants $45 to inspect the pump and another $150 to rebuild it, not counting the shipping to & from my shop to PSC in Texas. No thanks.

Today I will remove the defective PSC pump and install my original PS pump which has only 15,178 miles. I know for a fact that it works, is made in USA, and is free.

Thanks for all the comments.

 

[vanaisa]

If there are parts available, maybe you can repair your defective pump? "how hard this can be?" (Jeremy Clarkson).

 

[WWRD99]

Well, it's the pump. In fact, it's the new PSC SP1400 High Performance pump which lasted all of 20 minutes of driving. And because it has been eight years since I purchased the pump, obviously PSC will not honor the warranty. PSC wants $45 to inspect the pump and another $150 to rebuild it, not counting the shipping to & from my shop to PSC in Texas. No thanks.

Today I will remove the defective PSC pump and install my original PS pump which has only 15,178 miles. I know for a fact that it works, is made in USA, and is free.

Thanks for all the comments.

That sucks!! I don't know what brand that is but I will look it up. I'd bet an internal O ring ripped up in the valve in the back or the relief valve stuck. It is in the big nut that the pressure line bolts to. You can remove that without taking the pump off. Maybe something in there isn't right. It shouldn't need rebuilt since it hadn't been used. A stock pump works fine though. I got the reman ones from the local parts store. Most last some don't. Kinda the parts world we are in now.

 

[WWRD99]

That sucks!! I don't know what brand that is but I will look it up. I'd bet an internal O ring ripped up in the valve in the back or the relief valve stuck. It is in the big nut that the pressure line bolts to. You can remove that without taking the pump off. Maybe something in there isn't right. It shouldn't need rebuilt since it hadn't been used. A stock pump works fine though. I got the reman ones from the local parts store. Most last some don't. Kinda the parts world we are in now.

 

[cucvrus]

The stock pump is a better pump anyway. They have been on GM vehicles I owned for 50 years, and I only ever replaced a few that were manhandled by Godzilla and a 6 ft pry bar. The old Saginaw pump has been around for years. If you really wanted to go hi tech you could put an electric rack and pinion on it. HA HA By the way they don't make one that I'm aware of. The last 2 new GM trucks I had have the electric steering and it has been trouble free. Same as my Cruze. Have a Great Day. I've run more stock CUCV's running poorly then most other vehicles lasted period.

 

[Sharecropper]

The stock pump is a better pump anyway. They have been on GM vehicles I owned for 50 years, and I only ever replaced a few that were manhandled by Godzilla and a 6 ft pry bar. The old Saginaw pump has been around for years. If you really wanted to go hi tech you could put an electric rack and pinion on it. HA HA By the way they don't make one that I'm aware of. The last 2 new GM trucks I had have the electric steering and it has been trouble free. Same as my Cruze. Have a Great Day. I've run more stock CUCV's running poorly then most other vehicles lasted period.

Hey Rick! Good to hear from you. Regarding my PS issue - in re-thinking my actions during the project, I wish now that I had simply re-installed my original GM pump instead of opting for the PSC "High Performance" pump which lasted all of 20 minutes of driving. My original pump was Made in USA and only has 15,178 original miles. I am installing it today. Hopefully I can get the truck back on the road over the weekend to continue to certify all systems. Thanks for your post! Stay in touch.

 

[87cr250r]

There are kits available to rebuild the stock pump. It's just a shaft seal and reservoir o-ring. They are only a few dollars. Otherwise, the pump is a sliding vane type, these pumps can easily last 50-100k hours which is multiple engine lifetimes.

 

[Sharecropper]

There are kits available to rebuild the stock pump. It's just a shaft seal and reservoir o-ring. They are only a few dollars. Otherwise, the pump is a sliding vane type, these pumps can easily last 50-100k hours which is multiple engine lifetimes.

Thanks for your post and information. I am in the process of installing my OEM pump on the P400 engine so that I can road-test the truck. I would be interested in rebuilding the PSC pump with a kit when time permits. Can you provide more information on the kits? Source? Kit #?

 

[87cr250r]

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