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General Discussions about the 300M

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 #378887  by cos1776
 May 1st, 2019, 6:20 pm
Working on my Special and have the fuel rail and injectors removed and have a couple of questions.
1. The fuel rail has two arms the the injectors attach to, and each arm has what appears to be a swivel joint. One of the arms on my rail is nice and tight at the joint, but the other swivel joint is a bit loose and will spin rather easy. Is this a problem, and if so is there a solution for a fix or is a different rail in order?
2. Is the same o-ring used on each end of the injectors?
Thank you for any and all advice,
User avatar
 #378895  by remi
 May 2nd, 2019, 7:11 am
Hi John,

Have a look here (I know, russian site but hey it does the job :p) : ... I2OA%3D%3D

1. I have 2 rails sitting around and both have play at the joints. According to the part catalog the rail itself is not serviceable but if you have a spare, I guess you could try to?
2. Yes it is the same part number: 4418257 (last revision is 4418257AB, same o-ring for 2.7/3.2/3.5 btw, I used aftermarkets from RockAuto on mine).
 #378900  by cos1776
 May 2nd, 2019, 10:41 am
Thanks for verifying that the same o-ring is used on both ends of the injectors.
On the fuel rail "issue", I was doing a valve cover gasket replacement to fix an oil leak, didn't have a fuel leak. As long as I was in there, I also removed the lower intake to replace the o-ring on the coolant tube underneath. When I removed the fuel rail I noticed that the joint on the one arm was looser than the other one. So I am not sure if this is normal or a potential problem. I certainly don't want a fuel leak after I put this all back together, but I don't want to be concerned about something that is not an issue.
Anyone else have experience with this?
 #378997  by cos1776
 May 13th, 2019, 7:57 pm
As a follow-up to my question regarding play in the joints of the fuel rail, I reinstalled the rail as it was and pressurized the fuel system and have no leaks. So, from these results the answer to my question seems to be that a minimal amount of play is of no concern. However, if you remove your fuel rail I think it would be prudent to pressure test the fuel system prior to installing the upper intake plenum to be sure you have no leaks.