1972 350SL Questions

[rs899]

Anything I need to know before I try to pull the tank?

Yeah, extinguish your cigar. This ain't no diesel,paul.......

[meltedpanda]

lol

[DieselPaul]

Haha! True story, my cohiba was a safe distance away.

Got the tank out, its rusty inside, looks like I found my clogging issue. This is being discussed in the classic section, but thoughts on using the 3 step sealing kit from POR15 or KBS? I'll probably go KBS again because thats what Jegs stocks and they are under a mile away. The strainer was also deteriorating, so time for a new one of those too.

[Graham]

Originally Posted by DieselPaul

Haha! True story, my cohiba was a safe distance away.

Got the tank out, its rusty inside, looks like I found my clogging issue. This is being discussed in the classic section, but thoughts on using the 3 step sealing kit from POR15 or KBS? I'll probably go KBS again because thats what Jegs stocks and they are under a mile away. The strainer was also deteriorating, so time for a new one of those too.

I have used POR15 for many years and their stuff is usually good. KBS might be just as good?

But these coatings ain't cheap - Might be worth asking what a professional reseal would cost you and save yourself the trouble. I have seen prices around $150 in Canada, but probably less where you are?

[DieselPaul]

The KBS kit is $62.99, I used their system on my 300D tank, however it was a little less rusty than this tank.

The professional when I lived in Cincinnati wanted around $200 to do it.

The job on the 300D took two days to do, (dry time in between), and then you have to let the epoxy dry for a week.

[rowdie]

Did you find o-rings made from the proper material? If so where and what size. I have cleaned the fuel pump out of my junk '72 to save as a spare. It was pretty good and runs very quiet.

[DieselPaul]

I got a kitchen sink kit from lowes, it was $4. Its over at my garage, I'll try to measure it soon.

I went to Jegs to pick up the KBS kit, line was too long and I've got to get to work. So that'll have to wait until tomorrow.

[DieselPaul]

Working on the tank, I start by filling the tank with water and dish soap to get the easy to knock off crud out, yeah, its pretty obvious why my tank was clogging, lots of sandy flakes of metal, a lot like my 300D. Hopefully this solves my fueling problem.

I'll post some pics later.

[DieselPaul]

Well after a week of rain, I had the tank on the covered back porch, I opened the tank up and it still looks pretty rusty in there, and there was some water still in it and when I got it to come out it was nice and rusty colored. I'm going to hit Jegs tomorrow and pick up another bottle of rust blast and treat the tank one more time before I try to pour in the sealant. There don't seem to be any flakes of rust in the tank or anything like that and parts of it do have the dusty white phosphorus coating like they should but I think some remaining moisture in the tanke messed up the process, but I am going to re-treat it just to be on the safe side.

[DieselPaul]

Been bad about pictures, I'll try to get some up soon. Heres what I've been up to, the tank sealing process takes forever because you have to allow the tank to fully dry in between steps. We ended up doing the Rust Blast step twice, and the second step made a huge difference. I put the final sealant step in last night, looking in the tank a lot of tiny flakes got loosened up by the sealer, but according the KBS that is fine since they obviously will dry into the paint and won't be moving around.

I got a new strainer from Mercedes and I got a new hood pad, my hood shows some paint damage from the hood pad being gone. What type of adhesive do you use to put on a hood pad? And how do you propery remove the old hood pad? Obviously a serious covering job of the motor is in order.

This is it after cleaning

This is what came out, except 50x more, yeah, I think my strainer was restricted a little

[meltedpanda]

3M makes a spray on sealant and that is the stuff to use. Cover engine bay , remove old using a long bladed putty knife, carefull not to sctrach into metal.
spray and follow directions, have two people, put it on straight and slow, use a paint roller to get good adhesion once in place

I need a good hood pad, where did you get yours???

[DieselPaul]

I got it from auto house Arizona (dodging the filter here) for $48. It's "OEM" brand, cheaper than the dealer with my discount and cheaper than eBay because I needed a tie rod for my 124 which put me over $50 and got me free shipping.

[Graham]

Originally Posted by DieselPaul

I got a new strainer from Mercedes and I got a new hood pad, my hood shows some paint damage from the hood pad being gone. What type of adhesive do you use to put on a hood pad? And how do you propery remove the old hood pad? Obviously a serious covering job of the motor is in order.

I removed the old pad by brushing on a solvent and using a plastic or steel paint scraper. Be careful if you use the metal one. I can recall exactly which solvent I used, just something I had. Most likely paint thinner or parts cleaner would work. Contact cement thinner might work. I used coarse wire wool on some stubborn sections at end.

I took the hood off and laid it on a pair of saw horses. Makes it a lot easier to do and you don't get adhesive over everything (hood comes off easily)

Hood Pad Adhesive used was 3M #08090. Expensive but good. (Previous spray contact adhesive did not work - Maybe heat got to it and it fell off after a couple of years.)

"#08090 is a contact adhesive designed for bonding vinyl tops, heavyweight headliners and hood silencer pads where high strength and heat resistance are needed."

I bought 3 cans for two cars and applied it all. I applied it to both the hood and the pad. I put 2 coats on and then an extra one on the pad because it soaks into the foam.

Final step is also easier with hood off, because you need to carefully line up the pad with the hood.

[DieselPaul]

So I got the sealed tank in, NEW OEM strainer, new hose from tank to bubble box, new hose from bubble box to pump. Cleaned up the pump, put in 2 new o-rings, and tested it with 12v, spins freely.

Put it on the car, nothing.

Blew air through the line at the filter up to the line at the damper, air moving through it, so the line is free.

Hooked it back up, tried to run the car, nothing.

Fuel comes out of the check valve on the pump, so thats not stuck, it was, but I cleaned it up.

Fuel comes out the the exit to the filter.

So I jumpered the pump with a 12v charger to try to get fuel to make its way up to the motor, nothing.

So, I ran a 4 foot line off of the exit of the fuel filter to a container next to the car.

With the pump off, fuel runs through the line from the filter exit to the container.

So then I jumpered the pump, it slowed down the flow of fuel until it stopped.

So I ran the pump backwards, same result, slowed down the flow of fuel.

Popped the pump out, cleaned it out again with brake clean. Turned the pump up on end with the inlet up top. Put a funnel in it and filled it with fuel so it wouldn't run dry. I then ran the pump. The trickle out of the check valve slowed, and I got some bubbles.

So, is my pump bad internally somehow, or is it just a check valve problem?

[meltedpanda]

sounds like it to me , should blow out of there with at least 28 psi.
Can you post a picture of your set up