Hyd Pump bad?

Old Mustanger · 02-11-2022, 09:24 AM

Having trouble with the leveling legs on the Alpine coming down, especially when traveling. I did trouble shooting and couldn't find the cause so I took the trailer into a trusted repair place (not the dealer). They came up with the Hydraulic Pump is bad and are replacing it (covered by extended warranty thank goodness). I had not heard of this as a cause for this issue

, have any of the experts on here heard of it?

**chuckster57** · 02-11-2022, 10:04 AM

Legs creeping during travel is more likely a solenoid at the manifold. If the pump was bad, the rooms would creep too.

Old Mustanger · 02-11-2022, 01:23 PM

Quote:

Originally Posted by chuckster57

Legs creeping during travel is more likely a solenoid at the manifold. If the pump was bad, the rooms would creep too.

That's what I thought but they claimed to have tested the solenoid and the valves , and supposedly everything passed but the pump. I had thought it was the valves in the block. Thanks, guess I'll have to keep a close check on them when we get it back.

ChuckS · 02-14-2022, 05:52 AM

You were given the wrong information regarding your leveling legs creeping down....

The hyd pump isn't going to cause your issues..

You have THREE Hydac valves for the six point leveling system on that Alpine..

Front LG has ONE for both and there are two for the left and right mid/rear levelers..

Depending on WHICH leveling legs are creeping down you could have EITHER a Hydac valve that either isn't fully closed at its manual over ride screw or the valve itself isn't seating...

You could also have a leveler leg leaking internally which will bypass the needed hyd pressure to keep the legs retracted.

Example: if the issue is on the driver side mid/rear leveler legs creeping down I would evaluate that Hydac valve manual override screw for being fully closed and I would do an internal bypass check on those two levelers since they are connected in tandem

If tis just the front LG then evaluate the Hydac valve ON THE LG and do a bypass leak test

Old Mustanger · 02-14-2022, 09:05 PM

Quote:

Originally Posted by ChuckS

You were given the wrong information regarding your leveling legs creeping down....

The hyd pump isn't going to cause your issues..

You have THREE Hydac valves for the six point leveling system on that Alpine..

Front LG has ONE for both and there are two for the left and right mid/rear levelers..

Depending on WHICH leveling legs are creeping down you could have EITHER a Hydac valve that either isn't fully closed at its manual over ride screw or the valve itself isn't seating...

You could also have a leveler leg leaking internally which will bypass the needed hyd pressure to keep the legs retracted.

Example: if the issue is on the driver side mid/rear leveler legs creeping down I would evaluate that Hydac valve manual override screw for being fully closed and I would do an internal bypass check on those two levelers since they are connected in tandem

If tis just the front LG then evaluate the Hydac valve ON THE LG and do a bypass leak test

Thanks, it's the 4 rear levelers, I had tested all the levelers for internal seals leaking and they all passed, so I kind of figured it would be one or more of the Hydac valves. I had over tightened them at one time and thought I may have damaged the seats. Only took it to a shop to get them replaced since they would have been covered under the extended warranty. The shop insists that all 3 Hydac valves are OK and that the pump did not pass a LG/Lippert recommended test.
Chuckster57 had mentioned that if it was the pump causing it the slides would creep out also. They never creeped out but sometimes would "hammer" after retraction and to stop it I would have to extend them just a little then bring them back in. Does this give any clues?

ChuckS · 02-15-2022, 06:52 AM

Quote:

Originally Posted by Old Mustanger

Thanks, it's the 4 rear levelers, I had tested all the levelers for internal seals leaking and they all passed, so I kind of figured it would be one or more of the Hydac valves. I had over tightened them at one time and thought I may have damaged the seats. Only took it to a shop to get them replaced since they would have been covered under the extended warranty. The shop insists that all 3 Hydac valves are OK and that the pump did not pass a LG/Lippert recommended test.
Chuckster57 had mentioned that if it was the pump causing it the slides would creep out also. They never creeped out but sometimes would "hammer" after retraction and to stop it I would have to extend them just a little then bring them back in. Does this give any clues?

Since it is all four mid/rear levelers then it could have been the pump but this should have also affected the front LG and hyd slides as well..

The "hammering issue" sounds more like air in the system then anything else and could be removed by cycling the slides in and out a few times to purge.. its a self purging system..

First image shows how all four mid/rear levelers do have a common path on the retract side of the hydraulic flow... Image from Lippert after market manual

The front LG are not in this retract line side NOR are the hyd slide outs.. They each have their own... Of course the Frt LG are connected in tandem so what affects on affects the other...

Second image shows the test points on the hyd pump manifold that can be used for pressure test and leak test if you have the fittings and a gauge to connect.. Image from my Alpine hyd pump

One other thought is did anyone test the over pressure cutoff switch on the retract manifold? It is an electrical switch and would only trip if pressure is too high but those slides should simply stop once the slide switch power button is released

ChuckS · 02-15-2022, 07:47 AM

After looking at this Lippert TI on testing the system pressure I apparently am in error on my thinking of the hydraulic pump being the cause of those four mid/rear leveler legs leaking down after retracted...

I have to admit that I have not seen this issue.. it is usually a bypassing leveler leg, leak, or Hydac valve that hasn't fully seated...

Page 3 starts the pump pressure test procedure... Simple test...

https://lci-support-doc.s3.amazonaws...cd_0001910.pdf

**chuckster57** · 02-15-2022, 08:04 AM

This thread has been interesting, Chuck, thanks for the documtation.

ChuckS · 02-15-2022, 08:13 AM

I enjoy these threads like this one.. I've learned a few more things and the info will be useful down the road for me if I had hyd issues of this type... Info may be useful for others as well that are DIY guys/gals like many of us..

ChuckS · 02-15-2022, 08:20 AM

The one thing I can't wrap my aged mind around just yet is the retract side lines for all four mid/rear levelers are connected to the retract block manifold as is the front LG on a separate retract line ( but to the same retract block)

It would make sense ( to me ) that if the hyd pump has an internal leak allowing retract side to bleed down then this would also affect the front LG as they too are tied into the same retract block...

And Lipperts diagram matches exactly how my six point system is tied together with the addition of one more retract line for my hydraulic slide outs...

I will get my treadmill workout done and ponder this while on the treadmill...

Old Mustanger · 02-15-2022, 08:50 PM

Thanks for following up with more info. The shop called me today and informed me that the new pump and reservoir have been ordered from LCI but no ETA yet

(I didn't think fast enough to ask them if they checked on Amazon

)

I'll definitely let y'all know when I do get the trailer back if this fixes it.

Old Mustanger · 03-16-2022, 07:52 PM

Y'all were right, got a phone call today, new pump installed but system still failing, so they are going back to trouble shooting. I was too upset at the time to really discuss but I'm going to contact them tomorrow and offer suggestions based on your suggestions.

I'm still betting it's a Hydac valve.

ChuckS · 03-16-2022, 10:06 PM

Sorry they wasted your time the first time around.. I would have them remove and replace the two Hydac valves for the left and right Mid/Rear levelers..

Since you didn't indicate there are any issues with the Frt LG ( They have there own Hydac valve mounted on one Frt LG) then one of the two Hydac valves on the manifold isn't closing when 12 volts is removed from the solenoid

There are three Hyda valves on that block ( 2 for the mid/rear levelers ) and 1 for ALL hydraulic slide outs..

Old Mustanger · 05-11-2022, 07:44 PM

Thought I'd update. After replacing the pump and the Hydra valves, the leveling legs are still drifting down. The tech spent so much time on the phone with Lippert support that they decided to provide 2 new jacks at no cost, thinking that at least one of the existing jacks has a scored cylinder. They arrived yesterday so I'll be taking the 5er back Monday for installation. Not sure how the tech is going to decide which 2 jacks to replace, assume it may be more trial and error.

ChuckS · 05-11-2022, 10:47 PM

Since the hyd pump was replaced under extended warranty and you state that all 4 leveler legs pass their internal bypass test then I am curious as to what they think replacing two leveler legs is gonna accomplish?

If this fixes the issue then doing an internal bypass test per the Lippert Tech Bulletin is a worthless procedure

And which two legs they gonna replace?

If this was only one side (mid/rear) then I could maybe see the logic.

Question... was an internal bypass test ever performed on the Hydraulic slides... This is not usually gonna be the cause of your issue but the return side is all connected at one manifold...

Also wonder why the manifold was not mentioned.. it is a junction point for the return side of the system and if there is a crack internally this will allow all four leveler legs to bleed down..

This.. to me would be the most suspect item in the system since the shop states the pressure test on the original pump was failing the test..

New pump is also obviously gonna fail the pressure test on the system

Old Mustanger · 05-12-2022, 07:40 PM

all I know at this point is that the Tech indicated he ran every test that Lippert told him to and every test passed. I am going to ask him if he tested the slide hydraulics.
I agree that it doesn't make a lot of sense to replace 2 out of 4 jacks, but I'm not arguing with free parts at this point. I think he intends to start with the 2 on the left side since that side drops farther and more often.

Old Mustanger · 07-19-2022, 07:51 PM

Final follow-up (I hope). After 5 months, new hydraulic pump installed, 2 Hydac valves replaced and all 4 leveling legs replaced, it appears that this is finally fixed. This had the tech at the shop and techs at Lippert stumped as every test ran was passed including all 4 levelers continually passing internal leakage tests. They only thing they finally came up with is that 1 or more of them had a leak so small that the test would not show it but would still cause the leak down. Towed it home yesterday, about 30 miles, without strapping them up and had no leak downs.
I know extended warranties are not recommended but I sure am glad I had 1 for this mess.

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