Where is the inline fuel filter?? And other concerns ...

[1000nutsnbolts]

Good Super Bowl Sunday to All.

I bought a 1970 (manufacture April '70 113044 12) in October 2020. With it came scant records. Only service records from June/July 2018. That's all the documentation I have.

It's evident that the car has very few miles (11) added on the odometer in the last 3 years. When delivered, I went out for a very short drive. The car started easy and clean. Idle was smooth at RPM around 1K. But the car would barely run for the 1.5 miles I drove it. Really rough under load. 

In those few minutes, the odometer did register the ride.

Got it in the garage and up on stands. Siphoned and drained the gas. The siphon felt gritty and I had little doubt that about bad/stale gas.

Once empty, I got the fuel filter/strainer (BENZIN) out. Surprisingly, it didn't look bad at all. Not gummed. Bronze mesh not filled/clogged with particulate. Actually looks usable if I just brush it off.

Sender has some al oxide on surface as well as rust grit. Not terribly concerning. But there is heavy surface pitting below (bottom 1/4 of length) the 0.5mm diameter pin hole in side of cylinder. That pitting is noticeably greater below that hole than the 3/4 length above. I don't recall if the gauge was working properly.

Tank is out and currently being boiled and coated/sealed and external paint. With a little wrestling, that went pretty well. After it dried, I could hear debris/rust inside.

The fuel pump (large type) behind the drive side rear wheel looks newer. As does much of the tubing. From the pump to the engine the fuel line looks original.

So I need the cork sender gasket, a new BENZIN strainer, and a new gas cap (gasket on original is shot and gas was coming out fill when accelerating), some tubing for the venting at filler. Anything else?

Questions:

1) Should I be doing anything with the sender other than VOM continuity readings across the terminals while flipping it upside down?
2) I have to believe there is/was an inline fuel filter somewhere here. But where? Is fuel possibly being sent directly from the fuel pump/tank to the injection pump unit without any intervening fuel filter?
3) Can the evap control tank/etc be bypassed without sacrifice to performance? Those 2 small lines to fuel fill are going to be a bear on reassembly. Any tricks?


Further - as I mentioned, the car did start normally and with clean exhaust. Smooth idle. I believe that the fire/ignition source is all newer. Distributor rotor/points/cap/wires/plugs all look new as is indicated by service work records (July 2018, just 12 miles ago). Valve adjust performed at that time

The injection pump also looks newer. It is not the Bosch PES 6 KL 70 B 120 R22, but instead a Bosch PES 6 KL 70 B 120 R24.

I have no clue as to injectors. Keeping my fingers crossed.

Moving forward - I intend to reassemble and add 6 gallons of aviation 91 oct MOGAS. Check for leaks. New battery and start again for another ride.

Any suggestions?

BTW - Written by Mrfatboy - that F.I.P.i Fuel Injection Pump interactive simulator in the Technical Manual is awesome. If you haven't seen it - check it out.

Go TB Buccaneers!!!

[ja17]

The main fuel filter is mounted on the front left engine support, in an aluminum canister. It is unfastened with by loosening the 13mm bolt on the top. The canister is then removable from below. A new rubber o-ring seal should be used and must be ordered separately in most cases. It is similar to the one on the oil filter canister but is square in profile. Most important is to check the screen inside the intake fitting of the electric fuel pump. It is usually the first thing to get clogged.
You can rotate the fuel sender upside down a see if the float inside moves freely. With the ignition on you can also test to see if the fuel gage moves as you rotate it. It must be plugged in for this test of coarse. The sender comes from the factory with a tiny fill hole in the side. Also built into the bottom of the sender is another entrance for fuel to enter through a "micro maze" passage way. The "micro maze" prevents sudden fluctuations of the fuel gage during special conditions like steep hills, sudden acceleration or sudden braking and severe cornering driving conditions. The tiny nut on the bottom of the sender can be removed so the bottom can be removed. You can see and clean the "micro maze" and examine the float when the cylinder is removed. Be very careful since the float glides on tiny hair like wires which are easily damaged. Notice that the cylindrical outer housing "notches" into the top cover during re-assembly.

[Pawel66]

Perhaps I can add a bit:

1. Gas filler cap - it is very expensive item if you want to stay with original (not sure what yo currently have - there are threads on the forum on what an original should be) and there will be a key/lock question there. The gasket for this cap is separately available at MB dealers or e.g. SLS (I think Authentic Classic or Bud's Benz may have it too).

2. Tank venting - as the gas cap is not ventilated, you would need some kind of the system. The original one is not that complicated I think (I am an amateur and I was able to work with it with no issues). There are also numerous threads on the forum about both types (I do not know if you have the one with bigger tank on the left side of the trunk or the earlier one with a small tank in the rear right top corner of the trunk). If you have the tank out and you can work on making sure the vent "nipples" are not clogged, there are just some hoses and pipes that need to be connected. The difficulty in the system with small tank comes when the fittings in the small expansion tank are broken - you then either need a new tank or you need to fabricate the fittings (I made them out of a metal ball pen refill).

I am enclosing link to SLS pages that show how things looked like in a clear way: https://www.sls-hh-shop.de/main/en/mercedes-230-280sl-w113-47-fuel-tank-c-3_76

To get all the info you need you may look in the Technical Manual, use the search function on forum starting page, entering for example "gas filler cap" (with the parenthesis) or "fuel expansion tank".

Some owners add an intermediate fuel filter between fuel tank and fuel pump.

In April 70 280SL (mine is from March) you should, actually, have the small fuel pump. I am not sure how it works if someone fitted the large fuel pump and left the T connection in its tubing - I am just not sure if that is correct, someone more knowledgeable would have to say this.

[1000nutsnbolts]

Thank you Pawel.

I will reconnect the two vent lines. Access is tight tight. But I shall be patient.

Gas filler cap - I FOUND ONE!! Original NOS eBay -

https://www.ebay.com/itm/NEW-NOS-Genuine-Mercedes-Benz-190SL-W121-W111-W113-YMOS-Fuel-Tank-Cap-2-Keys-OE/264616791489?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D7f114847654b48b99b7a47709b842306%26pid%3D100675%26rk%3D4%26rkt%3D15%26mehot%3Dnone%26sd%3D283189450900%26itm%3D264616791489%26pmt%3D0%26noa%3D1%26pg%3D2380057%26brand%3DMercedes-Benz&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A825f7ec9-6ac5-11eb-826e-7e340d532ed5%7Cparentrq%3A866fca691770a4811e03c64fffe442b6%7Ciid%3A1

I will have to cash in on my wife's retirement to purchase.

Takes some time to acclimate to Tech Manual. As I mentioned, I get easily distracted.

Thanks Again - you are a good person!

[Pawel66]

There is no such access issue if you have the vent system with a small tank  - you can survive. The big tank system - I do not know.

On the gas cap - I have just checked and the system shows it is NLA (here in Europe). But before spending $1000, I would give a call to Tom Hansen in the US Classic Center and check the availability of the gas cap done to match your key number. Just in case. It was $300 at Mercedes when available.

I would always check ebay prices vs. Mercedes prices on serious items.

[1000nutsnbolts]

I was just joking. No way I am going $1.1k USD for a gas cap. I have a tranny project to tackle next.

I have the large evap cannister on left. I will just work it out to reconnect. I like how you used metal ballpoint pen refill tubes. That's creative.

US Classic was a help on getting the .pdf datacard from Germany mirco-fiche. I went to alpinaltd in Espana for artwork (EXCELLENT) and a local printer. Now I have a beautiful set of 5 cards. Just beautiful. @alpinaltd is a Magician.

I found a non-lock chrome cap on eBay that will work for $45.  A true original will have to wait.

Thanks Again.

[1000nutsnbolts]

Thanks Joe.

I will crawl around beneath today to locate.

The big help was your pointing out that square ring gasket/seal. I did find one that I hope is correct.

Is this the filter?

Mann 0000751132 Fuel Injection Pump Filter

[ja17]

Looks like it, there is an early and late one. I believe yours is the late version. Check the skinny nut wrench  size, early uses a 19mm and the later is 22mm.

[kampala]

1000nuts and Joe

I think you are discussing two DIFFERENT filters.   The one that joe mentioned in the first post  is a FUEL filter — the one that 1000nuts posted a picture of is an AIR FILTER for the WRD on the injection pump.  These are completely different.

See this to find the fuel filter location— confirm part number as thread maybe be a bit confusing but it will show show where to find the filter on the car. 

https://www.sl113.org/forums/index.php?topic=14292.0

[1000nutsnbolts]

OMG!!!  That link to the 2011 conversation was the answer. Thanks - and those photos in the thread!

I bought a Haynes Manual - no mention in there.

I did a search in our Technical Manual on "Fuel Filter" and didn't come up very much. Nada.

So today I did find it and added a photo here with arrow to the 13mm top nut on the housing. Needs two people, or a pillow underneath - that's heads up info.

Last - anyone want to offer - what is the filter designation, or P/N?

THANKS AGAIN

[Pawel66]

The main fuel filter is PN A 000 477 64 15, costs at Mercedes about $17 and comes with the seal. I buy it at Mercedes because it costs me same as MANN form internet store with shipment. But if you want MANN - internet stores have cross-reference number, I am sure.

However - I think it is not a bad idea to buy the air filter for Fuel Injection Pump - the one from your picture. It has a paper insert that, I suppose, disintegrated in your car. For 280SL the PN A 000 075 11 32 (optional with A 000 075 07 32). here the issue might be it costs about $100, so if you found MANN, you are at advantage.

If you call your MB dealer to confirm the fuel filter number, they will check it via part number search I suppose, but if they want to find it in the car - it is not shown in Fuel System, it is shown under Air Filter group. Just one of the EPC peculiarities.

[ja17]

Ah yes, I recognize the photo. It's Alfred's engine re-build underway at my shop back then.

[1000nutsnbolts]

Again - I sincerely wish to thank everyone for your help.

This Pagoda Group has been a Godsend.

Tom

[85lc]

Thanks for the info on the fuel filter.  I just checked and Pelican Parts has this filter.

I bought a NAPA Gold Filter 3167 which NAPA said was the correct fuel filter for W113s.  After an extended effort, we realized that the NAPA filter does not fit. 

The Mercedes and Mann filters have felt seals on both top and bottom.  The NAPA filter has rubber seals that prevent the canister from seating.  That is, the diamenter of the opening in the rubber seals is slightly too small to allow the canister to seat.

 

[85lc]

Wow, that is  a nice fuel cap and only $1,499 each and the ad says they sold several.  . 

[bracurrie]

FYI Tom Hanson retired from MB Classic center last year.

[rwmastel]

Most of this thread is from 2021.

[dakman29]

Just a caution. Before you open the fuel filter, disconnect the negative battery terminal. Ask me how I know

[Ed Riefstahl]

Hi Tom,

I've been reading your comments and it brings back memories of a situation I had about 10 years ago.
My 230SL was running absolutely perfect, got 1/2 mile from home and the car just shut off.
Turns out one very small grain of sand or dirt or something got from the tank into the pump. It lodged under the impeller blade, between the impeller of the pump and the backing plate causing the impeller quit turning.

Easy fix once I figured out why it quit. I put the pump back together and decided to put a $5.00 clear inline filter from NAPA on the rubber fuel hose between the tank and the pump, so any time I'm under the car I can simply take a peak at it and know absolutely for sure if I'm getting anything from the tank.

Just food for thought and a cheap, easy idea that can't be seen from the top side either.

Kind regards,
Ed R.
Erie, PA

1966 230SL (Ms Magoo)
1970 280S (Miss Daisy)
1989 300SE (Majestic)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - Red 5 speed (have you ever seen one?)
1997 Ford Ranger (Step Side 54K)
2023 Mazda CX 5

[rwmastel]

So today I did find it and added a photo here with arrow to the 13mm top nut on the housing. Needs two people, or a pillow underneath - that's heads up info.

No, many people here have done it themselves.  I believe I did it from below.  It can be messy!