Rebuilding SLS hydraulic pump

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3DB
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Rebuilding SLS hydraulic pump

Post by 3DB » Sun 19 Nov, 2017 2:27 pm

I thought I'd start a new thread on this as, true to form, I appear to have made some sort of mistake putting my pump back together after putting a seal kit through it.

I thought I'd paid proper attention when pulling it apart, but now that it is all back together, it is not pumping any fluid. Here's what I've done so far:
  • Opened bleed screw at levelling valve to relieve system pressure and left open;
  • Disconnected high-pressure return line that feeds into filter at top of reservoir and connected a flexible hose to drain into waste oil container;
  • Started engine and let the pump drain as much oil as possible from the system;
  • Shut engine down when reservoir was almost empty;
  • Removed reservoir, left levelling valve bleed screw open overnight to allow more dirty oil to drain;
  • Removed pump, disassembled, replaced o-rings & seals;
  • Poured in some clean oil to lubricate and avoid dry start-up;
  • Reassembled and connected all pipework;
  • Re-inserted levelling valve bleed screw;
  • Filled reservoir, but left high-pressure line feeding into the filter off with flexible hose into waste oil container;
  • Started engine expecting to see a mix of residual black oil, followed by clear oil into waste oil container;
  • Left engine running for more than 5 mins with no oil appearing;
  • Opened levelling valve bleed screw again - nothing but a trickle of old oil;
  • Shut engine down;
  • Brooded.
Before I pull it all apart again and try to work out what I've done wrong, is there anything I should check / try first?

I had a feeling I would regret my earlier statement saying this had been a 'satisfying project'.
Last edited by 3DB on Sun 19 Nov, 2017 8:53 pm, edited 1 time in total.
3DB
1976 W123 300D (weekend warrior on biodiesel)
1995 Holden Rodeo 2.8 factory turbo diesel ute (daily driver...also on biodiesel)
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mathuisella
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Re: Rebuilding SLS hydraulic pump

Post by mathuisella » Sun 19 Nov, 2017 8:23 pm

I have no idea, but i've got that spare if you need it :)

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kimrh
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Re: Rebuilding SLS hydraulic pump

Post by kimrh » Mon 20 Nov, 2017 12:09 am

Did you make sure the key was in place on the driveshaft that turns the pump when installing?
If not the pump shaft won't turn
87 White Euro 500SEC "ECE" 195kw
88 Black Euro 560SEC 220kw
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3DB
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Re: Rebuilding SLS hydraulic pump

Post by 3DB » Mon 20 Nov, 2017 1:20 pm

Did you make sure the key was in place on the driveshaft that turns the pump when installing?
If not the pump shaft won't turn
Hi kimrh - yes, I'm pretty sure that went back in
3DB
1976 W123 300D (weekend warrior on biodiesel)
1995 Holden Rodeo 2.8 factory turbo diesel ute (daily driver...also on biodiesel)
(@thirddegreeburns on Instagram)

tsharkey
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Re: Rebuilding SLS hydraulic pump

Post by tsharkey » Mon 20 Nov, 2017 3:11 pm

kimrh wrote:
Mon 20 Nov, 2017 12:09 am
Did you make sure the key was in place on the driveshaft that turns the pump when installing?
If not the pump shaft won't turn
Is the pump turning ?
W123 1981 300TD - Family Kid mover
W202 1998 C250D Factory OM605A Turbo - Partner's daily driver
W123 1982 300CD Retro fitted OM617A Turbo - Mine
W123 1984 300TD 5 Speed Manual, to teach the kids how to drive
W123 1982 300TD Factory OM617A Turbo (Hans) - Project
W123 1985 230TE - Brother's
W123 1985 300D - Sister in Law's
1962 S-Series Valiant (Tho Daimler & Chrysler divorced, still part of the extended family)

Past benzes
W114 1969 250CE - PO put in an M110 transplant and nearly sent me around the bend
W123 1981 300TD - "Matilda" - RIP hit front side & rear but left my brother + niece A-OK

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Coupe restoration, Turbo Wagon freshen up

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3DB
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Re: Rebuilding SLS hydraulic pump

Post by 3DB » Mon 20 Nov, 2017 4:59 pm

tsharkey wrote:
Mon 20 Nov, 2017 3:11 pm

Is the pump turning ?
It was turning by hand when it was off the car, but I guess it is impossible to know when on the car, but I would assume so. I definitely re-installed the little + shaped key and it can only go one way because the slots are 2 different sizes - one for the pump and one for the drive mechanism. There is a little chamfer on one side and I made a note when removing it that it faced out towards the pump.

It was quite fiddly reattaching the banjo bolt for the high-pressure output from the pump and I had to bolt and unbolt the pump housing a few times to get the threads started safely. It is possible that the key could have fallen out when mucking around with that, but I think I would have noticed. It certainly wasn't on ground.

I guess removing the pump again from the car will reveal that one pretty quickly.

I wish I hadn't filled the reservoir so full now with oil that costs $18/litre! But I'm sure I will only spill a couple of mL pulling the hose off again.
3DB
1976 W123 300D (weekend warrior on biodiesel)
1995 Holden Rodeo 2.8 factory turbo diesel ute (daily driver...also on biodiesel)
(@thirddegreeburns on Instagram)

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kimrh
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Re: Rebuilding SLS hydraulic pump

Post by kimrh » Wed 22 Nov, 2017 10:49 am

Gee there is no need to loosen the pump to install the high pressure banjo fitting.
But you do have to remove the high pressure line clamp fitting (13mm bolt) where the high pressure line feeds up above the SLS pump to create slack (movement) of the alloy tube to make it easy to install the banjo fitting by hand tightening ( on the M117 engine i always remove the viscous fan first to give good working space to get my hands in there) and i always place a rag just under the pump area to catch the copper crush washer in case it drops out when installing the banjo fitting.
If you re-built the pump correctly ( i never remove the spring loaded centre of the pump to change o-ring's or shaft seal) it should fire up fine with plenty of pressure as these pumps run up over 2,000psi. If an o-ring has not been installed correctly or has been pinched on install you will soon know about it as fluid will drip or run out of the housing onto the ground
87 White Euro 500SEC "ECE" 195kw
88 Black Euro 560SEC 220kw
89 Midnight Blue Euro 560SEL hydro 220kw AMG Kitted
http://www.flickr.com/photos/krh2013/sets/72157632548663623/
https://www.flickr.com/photos/krh2013/albums/72157668572599252

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3DB
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Re: Rebuilding SLS hydraulic pump

Post by 3DB » Wed 22 Nov, 2017 4:16 pm

Thanks, kimrh

I took it off again yesterday and pulled it all apart again and cannot see any problems.

I've since watched all available YouTube videos on it and I haven't done anything differently that I can see. Made sure I used all plastic / wooden tools on the internals etc.

It all turns freely by hand and makes what I feel like are the 'right noises' i.e. and intermittent sucking sound.

I did remove the spring-loaded pistons, which I now realise was unnecessary and I wouldn't have done it in hindsight, but they all look identical and I can't see how they have gone back together any differently.

Is it possible that when I totally drained the system I created some sort of air-lock?

If the pump does generate 2000 PSI, I guess that would blast any air out pretty promptly.
3DB
1976 W123 300D (weekend warrior on biodiesel)
1995 Holden Rodeo 2.8 factory turbo diesel ute (daily driver...also on biodiesel)
(@thirddegreeburns on Instagram)

tsharkey
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Re: Rebuilding SLS hydraulic pump

Post by tsharkey » Wed 22 Nov, 2017 6:31 pm

They self bleed so I doubt there is an air lock creating a problem.

Is the oil "disappearing" (ie: Into the engine ... Is the engine oil rising via the dipstick) ? I gather there are no external leaks.

Is the line and filter clear in the reservoir ?

Are you just being impatient and need to wait a while until it fully circulates ?
W123 1981 300TD - Family Kid mover
W202 1998 C250D Factory OM605A Turbo - Partner's daily driver
W123 1982 300CD Retro fitted OM617A Turbo - Mine
W123 1984 300TD 5 Speed Manual, to teach the kids how to drive
W123 1982 300TD Factory OM617A Turbo (Hans) - Project
W123 1985 230TE - Brother's
W123 1985 300D - Sister in Law's
1962 S-Series Valiant (Tho Daimler & Chrysler divorced, still part of the extended family)

Past benzes
W114 1969 250CE - PO put in an M110 transplant and nearly sent me around the bend
W123 1981 300TD - "Matilda" - RIP hit front side & rear but left my brother + niece A-OK

Current Projects
Coupe restoration, Turbo Wagon freshen up

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Re: Rebuilding SLS hydraulic pump

Post by 3DB » Wed 22 Nov, 2017 9:14 pm

Hi Tim - all good points and I need to go through all of these. I don't want to put the bugger back in again and have the same result.

So answering your questions:
tsharkey wrote:
Wed 22 Nov, 2017 6:31 pm
Is the oil "disappearing" (ie: Into the engine ... Is the engine oil rising via the dipstick) ? I gather there are no external leaks.
I don't think so. I put 2L in the reservoir and when I emptied it back out I had lost about 150 mL, some of which was spillage. So I don't think that is an issue. No sign of leaks.
Is the line and filter clear in the reservoir ?
I didn't even reconnect the filter - I just squeezed a bit of rubber hose (checked it was clear) over the end of the hard line and into a waste oil container to get the last of the old black oil out once the pump started doing its thing. I should open up the bleed nipple at the levelling valve and try to blow through the hard line I guess.

I put a new low-pressure rubber supply hose from the reservoir to the pump on also.
Are you just being impatient and need to wait a while until it fully circulates ?
Maybe. I reckon the car was running for 5 - 10 minutes though before I gave up, wondering if I was damaging the pump. Reckon I should try longer?

Even though the pump is very high pressure, it is also a pretty low flow rate. It took ages to drain the reservoir when I was first emptying the system. Maybe I didn't wait long enough?
3DB
1976 W123 300D (weekend warrior on biodiesel)
1995 Holden Rodeo 2.8 factory turbo diesel ute (daily driver...also on biodiesel)
(@thirddegreeburns on Instagram)

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Bartman4800
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Re: Rebuilding SLS hydraulic pump

Post by Bartman4800 » Thu 23 Nov, 2017 10:38 am

From a hydraulics point of view: (an SLS and/or power steering pump are nothing but a vane pump for the hydraulics afficionados)

They are notorious for not pumping after a rebuild, because the vanes sometimes stick a little in their slots when the pump chamber is empty.
Your output line towards your leveling valve might create a bit of resistance. Therefore the pump cannot get rid of the air bubble inside the pump.

Make sure there is a bit of "head" from the oil vessel to the pump (unbolt the SLS oil container and hang on the bonnet with a string)
Crack open the banjo bolt on the output of the pump. Gravity should now fill up your pump. It might take 5 minutes.
If you cannot raise the container, try a bit of over-pressure in the container to force the air out of the pump chamber.

Once the pump is full of oil, any air downstream is pushed out. Never let the fluid level go too low, cavitation can do a lot of damage!

Hope this helps, Bart
1963 220 Sb Sedan "Kermit" (Australian Assembly)
1960 220 Sb Sedan "Zum Schlachten" (Early German Assembly, with a torsion bar spring for the bonnet) - Stored in Country WA
1981 Subaru Brumby 1.8 with Weber and 5-speed box "little utie" - Sold to another enthusiast!
2006 Ford Focus "daily driver"
2002 VW Passat V6 30V Station Wagon (SOLD - This car into a money pit)
2011 Kia Sportage "Missus commuter Bus"
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3DB
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Re: Rebuilding SLS hydraulic pump

Post by 3DB » Thu 23 Nov, 2017 4:40 pm

Thanks, Bart.

Some simple priming of the pump.

I assumed the head from the reservoir was enough to self prime, but this makes sense if there is an air lock.

I should have connected the reservoir and filled prior to tightening the banjo, looking for fluid leaking out the banjo connection.

I'll try this on reassembly with crossed fingers.
3DB
1976 W123 300D (weekend warrior on biodiesel)
1995 Holden Rodeo 2.8 factory turbo diesel ute (daily driver...also on biodiesel)
(@thirddegreeburns on Instagram)

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Re: Rebuilding SLS hydraulic pump

Post by 3DB » Fri 24 Nov, 2017 7:04 pm

Success!

Took a lot of priming though.

Ended up pressuring the reservoir by mouth (well cleaned beforehand) and nearly popped a gasket doing it.

Could only get so far before I had to give the starter motor a quick squirt to rotate the pump a bit then reapply more pressure.

It worked though and now I have nice clean oil...for now.

Thanks again to all for the assistance in troubleshooting, especially Bart.
3DB
1976 W123 300D (weekend warrior on biodiesel)
1995 Holden Rodeo 2.8 factory turbo diesel ute (daily driver...also on biodiesel)
(@thirddegreeburns on Instagram)

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Bartman4800
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Re: Rebuilding SLS hydraulic pump

Post by Bartman4800 » Fri 24 Nov, 2017 7:16 pm

Getting a warm fuzzy feeling here :dance:

Glad I could help, and that your weekend started awesome!


Bart
1963 220 Sb Sedan "Kermit" (Australian Assembly)
1960 220 Sb Sedan "Zum Schlachten" (Early German Assembly, with a torsion bar spring for the bonnet) - Stored in Country WA
1981 Subaru Brumby 1.8 with Weber and 5-speed box "little utie" - Sold to another enthusiast!
2006 Ford Focus "daily driver"
2002 VW Passat V6 30V Station Wagon (SOLD - This car into a money pit)
2011 Kia Sportage "Missus commuter Bus"
2002 Mitsubishi Rosa Bus (converting it to a motor home)

tsharkey
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Re: Rebuilding SLS hydraulic pump

Post by tsharkey » Sat 25 Nov, 2017 9:22 pm

Thanks Bart, as there will come a time when I come up against a similar block ....
W123 1981 300TD - Family Kid mover
W202 1998 C250D Factory OM605A Turbo - Partner's daily driver
W123 1982 300CD Retro fitted OM617A Turbo - Mine
W123 1984 300TD 5 Speed Manual, to teach the kids how to drive
W123 1982 300TD Factory OM617A Turbo (Hans) - Project
W123 1985 230TE - Brother's
W123 1985 300D - Sister in Law's
1962 S-Series Valiant (Tho Daimler & Chrysler divorced, still part of the extended family)

Past benzes
W114 1969 250CE - PO put in an M110 transplant and nearly sent me around the bend
W123 1981 300TD - "Matilda" - RIP hit front side & rear but left my brother + niece A-OK

Current Projects
Coupe restoration, Turbo Wagon freshen up

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