SLS High Pressure hose. 1984 300TD - PeachParts Mercedes-Benz Forum

firstdiesel · #1 02-13-2014, 02:43 PM

I have been having issues with noise from the SLS and decided to rule out pump cavitation by replacing the high pressure hose and check the plastic pieces and see if maybe there was maybe an obstruction.

Well..... the PO had it changed at some point , because the hose has newer white writing on it (more than likely by someone who has no knowledge of the system), and they must have pitched the old hose with all the plastic anti cavitation pieces in it and installed a new one with nothing in it!!

I ran a coat hanger through the old hose and it is empty.

Does anyone have any suggestions on where I might get all of those plastic pieces together so I can get it to work right?

Thanks

firstdiesel · #2 02-13-2014, 04:08 PM

MB doesn't sell the plastic parts separately.

Anybody have a used high pressure hydraulic hose assembly that they want to part with?

kerry · #3 02-13-2014, 04:16 PM

Good luck on that. My recollection is that they resembled irrigation pop up head filter inserts?? Perhaps some of those might work.

firstdiesel · #4 02-13-2014, 04:53 PM

Good luck on what? Finding a used hose assembly? Don't tell me that, are they really that hard to find?

My biggest problem is that I have never seen a wagon at my local junk yards in more than a decade!! Ugh

I'll check into the filters, but I'm thinking they are too big. Maybe not, worth a shot.

unity · #5 02-13-2014, 06:51 PM

do you have a hydraulic hose supply place near you? they might be able to get you what you need.

firstdiesel · #6 02-13-2014, 07:22 PM

I do to get the hose, which was the plan, but when I opened it up there was no plastic inserts that keep the pump from cavitating. I'm assuming it has to do with back pressure on the pump. I'm not an expert, I could be wrong.

Do all hydraulic systems use these types of inserts, plugs, I'm not sure what they are called?

kerry · #7 02-13-2014, 08:29 PM

I don't think so. I think other members have hoses without the inserts and aren't experiencing problems.

vstech · #8 02-13-2014, 09:00 PM

Quote:

Originally Posted by firstdiesel

MB doesn't sell the plastic parts separately.

Anybody have a used high pressure hydraulic hose assembly that they want to part with?

I do...

sitting on my shelf.... along with the entire sls assembly if you need it...

two in fact... one is still in the car, an 85 euro td...

firstdiesel · #9 02-13-2014, 09:21 PM

Thx Kerry. Here's the thing, I've got a buzzing noise that changes exactly with my RPMs. I know there could be many other things that cause this, but I've narrowed it down.

With the car running, I can put my hands on the metal tubing that runs along the passenger side under the car and feel the vibration. If I go in the back, the noise is clearly coming from right where the hydro shocks are and the metal tubing that runs under there. I can hear it in the car and under the car. It actually changes pitch when going over bumps at speed when the suspension is compressed and released.

I bought a rebuild kit for the pump that seals everything that can be sealed, o-ringed or gasketed (made up word). I re-sealed the valve in the back, twice. I replaced both hydro shocks and all the rubber on the rear subframe, mounts (3) , trans mount and motor mounts. I've traced the exhaust to see if its touching anything, I've traced the SLS lines to make sure that the rubber bushings aren't disintegrating and touching and I've run out of things to look for.

I spoke with someone I know that is extremely knowledgeable about my plight and he said that it sounds like a cavitation problem, which leads me full circle to why I took it apart in the first place.

Maybe it is the shape of the old hose? I could just get a new hose and see if it changes. It could also just be a burn pump due to running dry before I bought the car, but it does level the car fine and I didn't notice anything when I had it open and pushed the pistons to see if they moved freely.

The suspension works properly when driving, not bumpy, and it fills properly. Just that buzzing/vibration noise all the time.

I am way open to suggestion, but when I previously posted this nobody really had the problem so they couldn't help.

Sorry for the short story turned long, but the plastic pieces were just the next step. I would love for someone to step up and tell me how they fixed this without replacing a $1000 pump.

Thanks to all that have pitched in on suggestions already.

Todd

firstdiesel · #10 02-13-2014, 09:23 PM

JOHN!! Read my previous post. Tell me your thoughts!

vstech · #11 02-13-2014, 09:29 PM

yup. cavitation from the lack of restriction in the tubing... there are several styles. I think I have the orificed tubing... I may also have the string of balls. I'll check if you need them...
any chance you'd throw that $1000 my way?

firstdiesel · #12 02-13-2014, 09:42 PM

Well you saved the day, if I had it to give, you'd be at the top of the list!! But alas I do not, sorry.

Thank you for the help, this has been driving me insane hearing it all the time I'm in the car!

unity · #13 02-14-2014, 10:31 AM

i have a solution that may be helpful to you, however my post was deleted because it is against forum rules as it mentions another parts vendor. i am aware of a rebuild kit available for the high pressure hose for the SLS. you can pm me for more info.

whunter · #14 02-14-2014, 11:36 AM

http://www.peachparts.com/shopforum/general-information/151991-self-leveling-suspension-%3D-sls-hydro-pneumatic.html#post1155925

.

kerry · #15 02-14-2014, 02:28 PM

Quote:

Originally Posted by unity

i have a solution that may be helpful to you, however my post was deleted because it is against forum rules as it mentions another parts vendor. i am aware of a rebuild kit available for the high pressure hose for the SLS. you can pm me for more info.

What is in the rebuild kit? All you need is a new piece of hose to rebuild it. The fittings are reusable.