1972 350SL Questions

[DieselPaul]

Thanks for the infor Graham! I read the benzworld link, I put some penetrating oil on the all the bolts and clamps on the fuel pump, I'll pull it soon and take it apart.

I ordered a fuel filter from Napa too.

The list from the indy says the brake fluid needs changed, but that's the only comment on the brakes, so with the help of my lovely assistant (my girlfriend) we worked a lot of new DOT4 through the system and have nice clear fluid coming through the system.

[350SL4spd]

Great Find!

I've seen many a solid Benz's relegated to storage due to a costly "to do" list from a mechanic. Get it running & drive it until something breaks, fix that bit, repeat.

One thing you'll need to do is read up on the D-Jet injection system in these cars. Search on here, there's tons of info. It's a good system but it definitely has it's quirks.

Looks like you're on the right track for getting the basics of the fuel system sorted. One quick test is to crack a line at one of the injectors and jump the FPR and see if you get anything. If not, crack the main fuel line that comes in from the rear of the car and try. Could help determine if the problem is under or the hood or back with the FP/tank.

Good luck!

[DieselPaul]

Well, I need some help. Does anyone have a color coded diagram for the fuel pump relay? I went to pull the relay out (got two spares today) and the back of the connector came apart and the red and black wires came out. I notice there are 5 pins on the relay, but only 4 wires, and I couldn't figure out which went back where. Help please!

Also, how do you pull the climate control face off? Mine seems too loose and the mechanical aspect of the fan knob sits too far back for the knob to click in.

[DieselPaul]

Todays improvements,








I don't have the after for this because my climate control was brittle and won't go back together, but I got the missing 'fasten seatbelt' light, the knob for the dash vents slider, and a new fan control knob.

[JohnM.]

Hopefully you are not too attached to those chrome fender trim pieces. I hate those so much.

Usually they are hiding rust, or they were installed with sheet metal screws so removing them would cause more damage than leaving them alone. I've removed a set successfully that used very small diameter rivets.

[DieselPaul]

Agreed on all counts.

However, this car doesn't have any rust under there, but due to the paint fading if I take them off I'll have bright red hoops underneath

[RadioTek]

Well.....

If nothing else, you could convince yourself that the fender trims will keep you from getting dings on the edges of the fenders.

I put a set on a W124 back in the early '90's and within a week, one had gotten 'doored' in a parking lot. It saved the fenders.

Although I cheated when I installed them, and smeared the back mating surfaces with RTV silicone to seal out any moisture from the inside between the trim and the body.

[Graham]

Originally Posted by DieselPaul

Well, I need some help. Does anyone have a color coded diagram for the fuel pump relay? I went to pull the relay out (got two spares today) and the back of the connector came apart and the red and black wires came out. I notice there are 5 pins on the relay, but only 4 wires, and I couldn't figure out which went back where. Help please!

Also, how do you pull the climate control face off? Mine seems too loose and the mechanical aspect of the fan knob sits too far back for the knob to click in.

I don't recall offhand. but the relay should have markings showing the connection numbers that are shown on wiring diagram. Wiring diagram shows wire colours. Rt is Red and Sw Black.

[DieselPaul]

The diagram says relay 54 is the fuel pump, but it only shows 2 wires going to it. The relay in question looks like the one you posted a photo of with 5 pins, however only 4 wires go to it.

Am I looking at the wrong thing?

[DieselPaul]

So I stopped being dumb and looked at the wiring. Considering the lengths of the wires and how they had hardened over time with curves in them, it would only go back together one way.

Back to starting for a second then dying.

I have been busy with school and haven't popped the pump out yet.

My girlfriend and I did bleed the front brakes, nice clean fluid in the whole system now. Front shocks are monroe, but look recent, most of the bushings look good. The way bar links are deteriorating pretty bad, but they are like $16 online, so I'll order a set up when I place an order somewhere.

[Graham]

Originally Posted by DieselPaul

The diagram says relay 54 is the fuel pump, but it only shows 2 wires going to it. The relay in question looks like the one you posted a photo of with 5 pins, however only 4 wires go to it.

Am I looking at the wrong thing?

The diagram says that item 54 is the fuel PUMP which does have two wires to it.

Check item 33.

[DieselPaul]

Got the fuel pump apart, was full of crud. Got it all cleaned out and pretty. Went to put it back together and realized the o rings were shot. They were pretty squished and when I put it back together and let fuel flow into it, it leaked badly.

So, is there any way to re-o-ring (the ovalish ones) the pump? NAPA only had rings that were too thick.

I did drain a ton of nasty brown varnished gas out of the tank and put in a new fuel filter.

[DieselPaul]

Bumping this up, does anyone have an idea of the o-rings?

[abiby]

Originally Posted by DieselPaul

Bumping this up, does anyone have an idea of the o-rings?

If you can determine the size of the o-rings required, I'm sure you can find them.

I'd try some industrial suppy houses Like Granger.com, or even a local hardware house rather than just the auto supply. Keep in mind they are probably a metric size.

[Graham]

First problem is to try and figure diameter of o-ring that will fit the pear shaped groove: