MW pump components// endless labyrinth - PeachParts Mercedes-Benz Forum

Shern · #1 03-30-2018, 07:00 PM

Okay.

Was swapping glow plugs a couple weeks ago and had my hardlines off. Noticed a few days later I’d failed to tighten one of the hardline clamps adequately because it was gone. Probably drove for 2-3 days before noticing. When I did notice, I saw the last two hardlines were shaking pretty hard around the mounting point on the IP.

Found a replacement clamp, all good. Then I began finding wetness on top of the IP -this is an MW pump- on the 4th fitting. Was convinced for some time I’d cracked the flare fitting on that 4th hardline. Not the case. Have been driving for two days with a white paper towel tied to the fitting. It’s completly clean. The top of the IP however is still seeping fuel.

Had a look at the manual. From what I can tell, the only thing in there that might be the culprit is a crush washer (BOSCH: 1410105020) Again, this is an MW pump -no o ring in the main part.

Before I spend any more time trying to find the damn thing (no luck at all)
Am I missing anything obvious? Is a shake/vibration enough to cause that seal to fail?

Shern · #2 03-31-2018, 03:21 PM

If the vibration did loosen the valve carrier, would it be a bad idea to re-torque to 40-50nm? The FSM seems very particular about doing this in one continuous movement. I don't know when I'll be able to find a new valve seal and I'd like to stop leaking.

leathermang · #3 03-31-2018, 03:25 PM

That crush washer is a one time use right ?
but you would be trying to fix the situation by just tightening the one already there ?

Shern · #4 03-31-2018, 03:29 PM

Quote:

Originally Posted by leathermang

That crush washer is a one time use right ?
but you would be trying to fix the situation by just tightening the one already there ?

It sure is.

Say the vibration loosened the valve carrier by 5nm and brought it down to say 35nm (original torque value being 40nm) -if I torqued to 45nm, remedy? No idea of crush washers work this way.

leathermang · #5 03-31-2018, 03:34 PM

Quote:

Originally Posted by Shern

It sure is.

Say the vibration loosened the valve carrier by 5nm and brought it down to say 35nm (original torque value being 40nm) -if I torqued to 45nm, remedy? No idea of crush washers work this way.

Why do you think the FSM is so specific about tightening it in ONE movement ?

Shern · #6 03-31-2018, 03:38 PM

Quote:

Originally Posted by leathermang

Why do you think the FSM is so specific about tightening it in ONE movement ?

Oh I gather that. I was just hoping there'd be an alternative solution. I called several Bosch dealers to no avail. This seals are a bear to find.

Diseasel300 · #7 03-31-2018, 03:43 PM

I've seen mentioned several times here and elsewhere that the copper crush washer for the DV is the same for the MW and M pumps. If so, they're readily available and cheap from a plethora of suppliers. You don't generally see the parts listed for the MW pumps since they almost never come apart, unlike the M pumps that need that O-ring changed every few years.

leathermang · #8 03-31-2018, 03:44 PM

We almost have the same car...
If you find them let me know where.... I might stock up....

Shern · #9 03-31-2018, 03:55 PM

Quote:

Originally Posted by leathermang

We almost have the same car...
If you find them let me know where.... I might stock up....

I know the dimensions... 14x10x0.5mm

These are the available seals, I believe used on the M pump :
https://www.pelicanparts.com/cgi-bin/ksearch/pel_search_2016.cgi?command=DWsearch&description=004-997-45-40-M14

Nowhere can I find the dimensions however.

moon161 · #10 04-02-2018, 09:58 AM

If it's a copper crush washer, you can just anneal it to it's soft state by heating above 700F.

Diseasel300 · #11 04-02-2018, 11:14 AM

My caliper says that the used crush washer from the M pump is 13.0 x 9.3 x 0.5mm. This is not a situation I'd re-use a washer due to the high pressure inside the IP.

Shern · #12 04-02-2018, 11:19 AM

Quote:

Originally Posted by Diseasel300

My caliper says that the used crush washer from the M pump is 13.0 x 9.3 x 0.5mm. This is not a situation I'd re-use a washer due to the high pressure inside the IP.

I think you're right... search continues.

Shern · #13 04-02-2018, 11:20 AM

When I eventually find them -my understanding is that cleaning the valves is in order. I take it a quick soak in carb cleaner? Also, to anyone who has also replaced the springs -was that necessary? Noticeable?

Diseasel300 · #14 04-02-2018, 02:14 PM

You want the entire top of the IP absolutely spotless before you break the first bolt loose. Use brake cleaner since it will evaporate quickly and won't eat up anything rubber/vinyl. We're talking SURGICALLY clean.

Inspect the DV's when you get them out. If they're pitted/scored/grooved, they're junk. They can have a layer of varnish built up on them that can be cleaned off. See the link in my signature line for some "light" reading.

I don't think the springs are required. I'm sure there are those that disagree, this is just my opinion. Having re-springed 2 IP's, the lengths were roughly the same. The old springs were a heavier wire, so for the same length, I'd expect them to have been slightly stiffer. Your mileage may vary. The springs are cheap enough that if you have to buy parts from the dealer, you may as well buy them and throw them in.

Shern · #15 04-02-2018, 02:28 PM

Quote:

Originally Posted by Diseasel300

You want the entire top of the IP absolutely spotless before you break the first bolt loose. Use brake cleaner since it will evaporate quickly and won't eat up anything rubber/vinyl. We're talking SURGICALLY clean.

Inspect the DV's when you get them out. If they're pitted/scored/grooved, they're junk. They can have a layer of varnish built up on them that can be cleaned off. See the link in my signature line for some "light" reading.

I don't think the springs are required. I'm sure there are those that disagree, this is just my opinion. Having re-springed 2 IP's, the lengths were roughly the same. The old springs were a heavier wire, so for the same length, I'd expect them to have been slightly stiffer. Your mileage may vary. The springs are cheap enough that if you have to buy parts from the dealer, you may as well buy them and throw them in.

In that case, it might be worth tracking down a source for valves . With the difficulty I'm having finding seals, I'd much rather open only once.

Thank you!