Fuel Pump to Check Valve Adapter for 450SL

[DAVID LEE]

I have a 77 450SL and I'm looking for the adapter that allows the newer check valve to be fitted to my older fuel pump. Everyone I have talked to doesn't know what I'm talking about, so here's a little background.

In an earlier thread concerning hard starting when hot, it was explained that the cause can ofter be a bad Accumulator, or check valve. Well, after troubleshooting it appears that both items are bad. The accumulator was definitely bad, and the check valve (which if I even have one is internal to the fuel pump) needs to be added. The problem is, the threads on the check valve are not the same as those going into the output of the fuel pump.

After doing some Googling this weekend, I found what I needed on ThePartsBin.com. After searching for fuel pumps and locating my fuel pump, I noticed that it comes with an "adapter". Of course, they don't sell just the adapter, and I don't need a fuel pump. The "Adapter" is all the way to the left of the image just below the fuel pump.

Thanks for any help anybody can give.

Can anyone help me locate a source for the adapter, or tell the part number of a check valve that will fit the fuel pump. I'm enclosing a picture of the fuel pump and displayed on ThePartsBin.com

[cth350]

Walk into a good hydraulic hose shop with the pump and the thing you want to adapt to and they'll set you up with the right parts. Save them some time and remind them that it's metric thread.

Much to my annoyance, I needed a similar adaptation for a Solex 4A1 carb and it took FOUR pieces of brass and steel to do it (10cm worth of kludge) and 20$ for the parts.

I expect you to have more luck than I did.

-CTH

[ozawa]

david lee,

i'm a little confused about your post. do you have a '77 450sl as you note in your post and heading, or a '77 euro 350sl?

if the picture you posted is indeed the pump that's in your car, the check valve is already screwed into the pump, (right side of photo.)

for US SL's from 76 to 85 (450SL through 380SL) they all used the same pump. a Euro SL though could be a different story...

[DAVID LEE]

It is a 350 SL EURO, but it seems to always confuse folks, so I just say it is a 450SL if the parts are the same (and in this case they are).

The part you see soming out of the fuel pump is NOT a check valve, but merely the mounting stem for the fuel pump hose. The check valve looks exactly the same (as I'm sure you know).

Anyway, what you would do is remove the mounting stem shown in the picture if you want a check valve installed and install the check valve in the mounting stem's place, but ONLY after you have installed the adapter. This you would do if the check valve in the fuel pump has gone bad, and all you want to do is buy a check valve (which is much cheaper than a $200 dollar fuel pump).

FastLane has said I just need to go to a good hydraulics shop and find a fitting that works and it looks like that's what I'm going to have to do.

thanks

[DAVID LEE]

Eureka!!! - I found what I needed.

If you ever need to add a check valve to an old Pierburg fuel pump that won't accomodate the new style check valve because of the threads, you can use a Porshe check valve - part no. 944-608-951-00. It's a perfect fit.

I begged for help at an independent MB shop and this shop had several old timers and they searched in their parts bins until they came up with I needed.

Anyway, hope this helps, and the $17 check valve was certainly cheaper than a $225 dollar fuel pump (to replace a perfectly good fuel pump).