Author Topic: Tall Fuel Pump Leak  (Read 6520 times)

mrfatboy

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Tall Fuel Pump Leak
« on: October 28, 2014, 18:25:19 »
Hello,

My 280sl's tall fuel pump just started to leak.  I have read the tech manual as well as all the threads.  While I was searching I came across this thread

http://www.sl113.org/forums/index.php?topic=15235.0

 which pretty well sums up my options.  I was going to buy the fuel pump rebuild kit but I noticed that OLAZZ still had a problem with the O ring size and his rebuild was a failure.  I tried to PM him to get more info but it would not work as his inbox is full.  I'm am not sure if he is still a member or not.

I'm confused about the O-ring size.  It sound's like the one in the kit is not sufficient and a custom one has to be built/sized. Does anybody know of the exact size I need? Source? This seems like a little black magic to me since it's my first rebuild.  I'm trying to determine the hassle factor vs. $600 :)    Should I rebuild or buy a refurbished tall pump.

I see the refurbished tall pumps are about the same price as a new short pump.  However, If I stick to the tall pump I would not have to buy another conversion bracket and cut into my protected covering to make gas lines fit. A job I'm not sure how to do anyway as I probably don't have the correct tools.


If I do try to rebuild do I really need to buy the $100 kit or can I just get the O-ring?  Of course, that is assuming I don't snap any screws.

Any other place to get rebuild kits?  I have sent a PM to George Des several days ago but no answer as of yet.

Any other tips would be greatly appreciated.
1969 280sl (Aug 1968 build)
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4 Speed

George Des

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Re: Tall Fuel Pump Leak
« Reply #1 on: October 29, 2014, 20:30:25 »
Tried responding via a PM but the inbox is filled. I do not have access to the spares parts I normally make these kits up from. As far as the armature oring goes, the best bet is to follow the thread where I describe how to size the oring by sanding while the armature is rotating in a drill press. I have never been able to get the proper seal with an oring right out of the box. This process should be added to the Tech Manual if it hasn't already been. I think it is a superior way to achieve the seal and eliminates trying to find the proper size metric oring which I'm not entirely sure really exists!  If this sealing is not achieved fully, the pump will ultimately leak. With a little bit of practice and patience, the sizing process is not that difficult and will allow you to get the proper seal between the bellows and the armature shaft. Hope this helps.

George

mrfatboy

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Re: Tall Fuel Pump Leak
« Reply #2 on: October 29, 2014, 20:44:15 »
George,

Thanks for responding.  That is interesting that you also got an "inbox Full" error. I didn't know there was a limit.  I just have a couple of old PM's in there.  I wonder if something is wrong with the PM system.

Do I really need to buy the whole rebuild kit or just the one o-ring assuming I don't break anything else when I take it apart?

What size of O-ring should I start with for the armature?  This one seems like the critical part.  Once you attempt a new O-ring seal what method do you use to test if it leaks without putting it back on the car if that is possible?
1969 280sl (Aug 1968 build)
Signal Red
4 Speed

George Des

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Re: Tall Fuel Pump Leak
« Reply #3 on: October 29, 2014, 20:58:15 »
I do not have the size handy, but it may be as small as an 001. It needs to be stretch and sort or rolled over in to place. Try a few small sizes. If it goes on too easy, it is probably not right. You really should replace all the orings but you can get away with just the armature  oring and the bottom cover one if you have to. As far as testing before you install. If the bellows seal is difficult to seat because the orings is holding back the bellows you are about right. It should take a little bit of force to get it to just allow you to set the snap ring-no more! Once the pum is assembled. I normally will test it using diesel or kerosene in a small bucket hooked up with some hoses. I think Naj shows this in one of his posts.


mrfatboy

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Re: Tall Fuel Pump Leak
« Reply #5 on: November 06, 2014, 09:18:54 »
I'm going to try to fix the pump myself. If I fail I can always buy a new short one. So the bare minimum of parts needed are:

1 - 5mm x 1.0mm Vinton o- ring
1 - pump cover Vinton o-ring
6 - m4 cheese head screws

From the pictures the 5mm x 1.0mm looks like square cross section as opposed to a typical round cross section. Is that true? Does it matter?

What is length of the m4 screws? Are they supposed to be stainless steel?

What is the size of the pump cover o-ring?  I got the part number from the tech manual. They are $35 from the dealer. Can I source it somewhere else for cheaper? Where?

« Last Edit: November 06, 2014, 09:23:06 by mrfatboy »
1969 280sl (Aug 1968 build)
Signal Red
4 Speed

Peter van Es

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Re: Tall Fuel Pump Leak
« Reply #6 on: November 06, 2014, 14:25:40 »
George,

Thanks for responding.  That is interesting that you also got an "inbox Full" error. I didn't know there was a limit.  I just have a couple of old PM's in there.  I wonder if something is wrong with the PM system.

Check this post: http://www.sl113.org/forums/index.php?topic=19572.0

You need a Full Membership for more than 10 PM's.
1970 280SL. System Admin of the site. Please do not mail or PM me questions on Pagoda's... I'm not likely to know the answer.  Please post on the forum instead!

mrfatboy

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Re: Tall Fuel Pump Leak
« Reply #7 on: November 06, 2014, 17:36:45 »
Check this post: http://www.sl113.org/forums/index.php?topic=19572.0

You need a Full Membership for more than 10 PM's.


I had a full membership last year. I have not reward. I currently have 38 messages and it says 38% full. Will deleting them fix the problem or is something else wrong?

I'm guessing the 38% full is reflective of when I was a full member and  the PM system didn't update when I reverted back to normal status?
1969 280sl (Aug 1968 build)
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4 Speed

Peter van Es

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Re: Tall Fuel Pump Leak
« Reply #8 on: November 07, 2014, 08:55:49 »
You will need to delete all messages in your Inbox AND your Outbox. Then you'll have room for 10.
1970 280SL. System Admin of the site. Please do not mail or PM me questions on Pagoda's... I'm not likely to know the answer.  Please post on the forum instead!

mrfatboy

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Re: Tall Fuel Pump Leak
« Reply #9 on: November 07, 2014, 18:11:39 »
You will need to delete all messages in your Inbox AND your Outbox. Then you'll have room for 10.

Ok,  Everything is cleaned out.  Now everybody can PM me again  ;D

BTW,  I have run into this problem when PMing other members.  I assume their inboxes are full and don't know it also.  It might be a good idea to make a sticky or remind everybody somehow to clear out their inbox.
1969 280sl (Aug 1968 build)
Signal Red
4 Speed

Garry

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Re: Tall Fuel Pump Leak
« Reply #10 on: November 08, 2014, 01:37:19 »
Or alternatively just pay the $30 pa subscription and help us keep the forum going.  You will even receive the Pagoda World and Pogoda Notes and get full access to the Tech Manual

Garry
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