How Do I Fix A Leaking CSV

[DavidBrough]

I have a problem stopping my CSV leaking and hope someone may be able to advise me on a fix.

I have been having cold start problems for a while which got a lot worse now the weather has cooled down so I decide to do something about it.

Carried out the usual tests and found the solenoid and TTS working OK but a slight weep of fuel from the centre bolt when removed, blocked internal jets and the in line filter a bit clogged. At this stage and, whilst having a full house of problems, I was happy at having isolated the issues and was quite confident of fixing things.

Unfortunately it didn’t prove as simple. Whilst the blockages were soon remedied with carb cleaner and the air line, I just can’t get the fuel valve to seal. Once everything was cleaned and re assembled the leak at the centre bolt seemed worse. Numerous further attempts have made no difference what so ever and the valve now leaks very badly.

I have the system with a small brass/bronze valve about 2cm long and first tried lapping it in with rubbing compound and when that didn’t work I tried fine grinding paste but all to no avail. At this stage I have been rather gentle with it as I don’t want to do any permanent damage assuming I haven’t already.

I am now left wondering if I should be more butch with it or is the use of grinding paste terminal. Also, could the problem be with the spring and is it possible to check the tension. Mine compresses and expands OK with a free length of about 15mm.

I hope it is reparable as it seems that parts are not available and new ones cost a fortune.

Thanks.

David Brough
1969 280SL

[Jonny B]

This has been discussed beore.

I used the search function, with "CSV repair", the thread with the title "CSV valve" should give you what you are looking for.

Good luck

Jonny B
1967 250SL Auto

[DavidBrough]

Thanks Jonny, a search on "CSV Valve" took me to Joe Melton's post where he used grinding paste and a drill to seat his valve.I Think I will just have to be a bit more butch with mine.

Sometimes it can be quite difficult to find what you are looking for due to the large amount of information available. I did try various CSV searches but must have missed Joe's post among the many responses.

[DavidBrough]

Well it looks like my leaking CSV is now cured but it proved a painful process and I would like to pass on a word of warning to others with the same problem.

I had tried everything to re seat the fuel valve from T-Cut and rubbing compound to fine valve grinding paste but all to no avail. Eventually and after many hours I gave up and sent it to SL specialists Roger Edwards Motors who promptly condemned it as I had ground away too much metal.

Thankfully they were able to provide a serviceable replacement for £150 but said that no more than T-Cut should be used on these valves. Apparently my use of grinding paste had also enlarged the hole the valve runs in which exacerbated the problem.

So the message is be very careful when re seating the CSV fuel valve and if you are not sure get a professional to do it.



David Brough
1969 280SL

[n/a]

.....Here is my five cents worth:

I had great succes in fixing any "EXTERNAL" fuel leak problems, including the CSV, with WELD-BOND. That stuff is very much gasoline compatible.

CHEERS !
WITT !

( PS: in my case: Leaky fuel-pump, gas-tank and CSV. Three years ago, still holding.....)      

 

quote:Originally posted by Jonny B

This has been discussed beore.

I used the search function, with "CSV repair", the thread with the title "CSV valve" should give you what you are looking for.

Good luck

Jonny B
1967 250SL Auto