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Need Help After Ps Pump Rebuild And Alternator Replacement


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Sorry for the long post in advance, but I've searched and finally did this big maintenance and now I'm stuck.

OK, so I just finished rebuilding the PS pump, putting on a new alternator and v-belt, and changing the distributor caps/rotors. This is on a 97 LS400 with 129k miles.

Now, there is a constant and VERY loud growling from the engine. It sounds like it's the PS pump, but like it's the pulley or something. It has me stumped.

The PS pump rebuild was all new seals and bearing. The pump also has an idle air valve that's only got about 4k miles on it. I also added an inline Wix magnetic transmission filter as well as the $1.99 cheapie inline Cardone PS filter both on my return hose.

I had a Gatorback belt on the car when I put it back together, but it was making this groaning noise and the tensioner read a little too tight on the range stamped on it. I swapped the belt for a Duralast (from Autozone) which shows that it should be the same belt size. The groan is maybe a little less, but still there and still VERY loud. The groan can be heard from inside the car and it feels like there is engine wobble. I double checked the clutch fan and it is on tight.

Filled PS reservoir with new fluid and turned wheels lock to lock about 50 times to relieve air from the system. I had the regular PS "groan" before, but this is easily 3 times as loud.

The main problem that concerns me more than the groaning though, is the power loss. My idle is just about where it should be, between 700-725 rpm. However, when I put it in gear to drive, there is a HUGE loss in power compared to previously. It feels like there is an occasional stumble/misfire, but basically it just feels like the emergency brake is on or something, if that makes sense. I can hit the accelerator and it will move, but as if I were towing something behind the LS.

When I punch the gas hard, the groan makes it sound like a toy car, and it will accelerate, but about 1/5 the power it did previously. Please help me figure out what I screwed up on this?

My questions are these:

1. What can cause this "groaning" from the PS pump with a new bearing/seal kit just installed?

2. Could a belt that is just too tight cause this groaning by putting too much strain on all of the pulleys?

3. What are the chances that the belt tensioner is bad, but still showing too tight on the markings?

4. Is it possible to put the distributor rotor on upside down / backwards? If so, should it have been hard to put on and screw in place?

I appreciate any help y'all can give, and if anyone in Austin, TX would be up for lending another eye/ear, I would be especially grateful. I am mechanically inclined, but my experience is with Datsun/Nissan Z cars. Obviously, this Lexus is a bit finicky for me to figure.

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First of all my LS400 is an earlier one so yours may be different but I don't think so. To solve your problem it's process of elimination. I'd be taking the belt off first and running the engine without it for a minute or two. If all is quiet you know the problem is either the belt, pump or alternator. Check for play in the pulleys etc. These cars can be a pig for getting air out of the pas system and air does cause noise. On my car the belt tension is automatic as the idler is spring loaded. Check the pulleys all line up in case you've got somthing out of line. If there is any play in any pulley it needs replacing. I'm sure your problem won't be serious, good luck.

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Just found another thread from 92lex where he said that rotors can be put on backwards/180 degrees off. Gotta tear down in the morning to get to the passenger rotor that I'm not 100% sure is on the right way. Unless it keeps me awake thinking about it tonight and I do an all-nighter.

Doh... hope I didn't just not pay attention on this one.

Will also leave the PS cap off to let any air drain out that will come on it's own and try to evac more bubbles in the morning as well.

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I doubt that the engine would start if the rotors were 180 off.

I recently rebuilt my p/s pump and new alternator added. I had a very hard time de-airing after the install. Finally on some advice from friends on this forum. I jacked the front end off the ground, placed a drain hose from the return line to a pan, and proceded to hand turn the wheels prob. more that 50 times in each direction. Until no air bubbles in the hose. I used a clear hose and had to cut it as short as possible because the fluid/air would not always exit the hose into the pan. And when you turn the wheel in the opposite direction it will suck some fluid back toward the pump with the air also. I did have the end of the hose under p/s fluid. After cutting the hose back I finally cleared all air.

I had tried to de-air with the engine running on and off for a couple of days. Still had an awful groaning sound with just the engine running and with turning the wheel a high pitched squeal.

After the manual de-airing I started her up and she was as quite as could be.

Also I made this mistake but fixed it before re-installing the pump. I had put the pressure valve in backwards ( where the high pressure hose attaches )

It fits in the spring better that way so I thought that was they way for it to go. But re-checked the pics and saw it was wrong.

You also could, but doubt, have a bad new bearing. But that should not affect your engine power. Caps and rotors can get cracked on install. check that you are not off on one or more of your ignition wire placements. Also, it could be possible that with the pump r&r or the new serp. belt you could of loosened a crank sensor wire.

Good luck

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Alright, so getting a new belt solved the issue along with draining the air out of the PS again.

In case anyone thinks about buying them, both the Duralast 875K6 and Gatorback 4060875 (only available belts in stock from Autozone) are too small for the LS400. I finally went to O'Reilly's and bought a Gates K060878.

Tensioner is now within the range it should be and the groaning is gone. Thanks for your input bigste and 93ls400walt.

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Glad it's fixed. I have gotten in trouble a few times by doing more than one repair at the same time. Then having a problem and not sure which repair was at fault. But I keep doing it!

Great tips here guys--thanks!

If you can see visible leaking of PS fluid around where the high-pressure hose attaches to the pump, would you safely assume the PS pump itself is still ok, and would only need to replace the hose? (This hose is ~$300!) :o

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What was advised to me was that the O-Ring from the reservoir where it connects to the P/S pump was leaking. In fact mine was and as it is under the flange it is hard to see. It then runs down and covers the high pressure bolt and so it looks like the hose is leaking. I wiped everything off and stuffed a clean paper towel all around and under the flange of the res. drove some and let it sit. The paper towel was wet iwth p/s fluid and the pressure hose bolt was dry.

Also, I could see p/s fluid welling up at the top round indentation on the pump body. ( at the top of the pump, coil side, 180 degrees from the high pressure bolt. This is where the high pressure valve/spring assembly fits. and the is an O=Ring on that end also.

So I had 2 leaks. I bought a seal kit for $24.00 from park place lexus. I only replaced the external o-rings and not the bearing or shaft seal

You need a vise and slide hammer to do this. I

Fixed all of my leaks.

You can request an additional res. o-ring which I did and was glad of that as on re-assembly the o-ring broke as I was inserting the res to the pump body.

If you do this loosen all bolts that you can while the unit is still on the car. Especially the high pressure nut that the hose banjo washer attach to. the You really need a vise though to remove the 4 bolts holding the pump body together.

need

1) seal kit

2) extra 0-ring

3) banjo washer

r

4) stuff for de-airing flush, new low pressure hose, vise, torq. wrench

5) lots of hand cleaner

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What was advised to me was that the O-Ring from the reservoir where it connects to the P/S pump was leaking. In fact mine was and as it is under the flange it is hard to see. It then runs down and covers the high pressure bolt and so it looks like the hose is leaking. I wiped everything off and stuffed a clean paper towel all around and under the flange of the res. drove some and let it sit. The paper towel was wet iwth p/s fluid and the pressure hose bolt was dry.

Also, I could see p/s fluid welling up at the top round indentation on the pump body. ( at the top of the pump, coil side, 180 degrees from the high pressure bolt. This is where the high pressure valve/spring assembly fits. and the is an O=Ring on that end also.

So I had 2 leaks. I bought a seal kit for $24.00 from park place lexus. I only replaced the external o-rings and not the bearing or shaft seal

You need a vise and slide hammer to do this. I

Fixed all of my leaks.

You can request an additional res. o-ring which I did and was glad of that as on re-assembly the o-ring broke as I was inserting the res to the pump body.

If you do this loosen all bolts that you can while the unit is still on the car. Especially the high pressure nut that the hose banjo washer attach to. the You really need a vise though to remove the 4 bolts holding the pump body together.

need

1) seal kit

2) extra 0-ring

3) banjo washer

r

4) stuff for de-airing flush, new low pressure hose, vise, torq. wrench

5) lots of hand cleaner

93ls400walt--thanks...that makes perfect sense: my PS leak didn't BEGIN until after I removed the reservoir to clean out the screen as preventative maintenance. Could be that I damaged the oring upon reinserting the reservoir.

BTW, why did you require a new low pressure hose--I thought your leaks were only from o-rings?

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You can use any similar sized reinforced hose that is graded for automatic trans. fluid. Don,t recall the size, I took my res. to autozone and found a proper hose to fit. Buy more length than you need. Connect it to the incoming line then route it to the res. with a gentle curve, no kinking, and cut off the extra. New hose clamps won't hurt either.

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