Author Topic: Barometric compensator (BC) removal quick questions  (Read 1996 times)

Greg R.

  • Associate Member
  • Junior Level
  • *
  • USA, DC, WASHINGTON
  • Posts: 24
Barometric compensator (BC) removal quick questions
« on: December 02, 2019, 13:37:37 »
Good morning.

1) What size wrench fits the hex section?  (17mm?)
2) Must a thin tappet-style wrench be used or is there another technique?  My search here last night didn't turn up anything.

-Greg
1967 230SL w/ 250 motor
Greg R.
Washington, DC
W113 1967 230SL (auto, 250SL motor)
E24 M635
E38 740i sport
S3 Spider Veloce
ex-E32 735i, ex-E24 635CSi turbo, ex-1965 Falcon Futura convertible (301W H.O. transplant)

jeffc280sl

  • Guest
Re: Barometric compensator (BC) removal quick questions
« Reply #1 on: December 02, 2019, 14:33:16 »
The baro requires a 19 mm wrench.  I think youre on the right track for its removal.  Been a long time since I replaced my baro

wwheeler

  • Vendor
  • Platinum
  • ******
  • USA, TX, Dallas
  • Posts: 2862
Re: Barometric compensator (BC) removal quick questions
« Reply #2 on: December 02, 2019, 16:09:02 »
Be on the look out for thin shims under the BC when you take it out. Not sure why you are taking it out, but some use this to do a quickie full range fuel mixture adjustment. You can also test the compensator to make sure it hasn't failed while it is out.  https://www.sl113.org/forums/index.php?topic=12175.msg82217#msg82217

Jeff knows quite a bit about these pumps.
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

Shvegel

  • Associate Member
  • Platinum
  • ******
  • USA, OH, Cleveland Heights
  • Posts: 2978
Re: Barometric compensator (BC) removal quick questions
« Reply #3 on: December 02, 2019, 16:12:12 »
I walked out to the garage and slipped the fattest 19mm I had (.35 inches thick) onto the baro of my 1970 and it worked fine.

Greg R.

  • Associate Member
  • Junior Level
  • *
  • USA, DC, WASHINGTON
  • Posts: 24
Re: Barometric compensator (BC) removal quick questions
« Reply #4 on: December 02, 2019, 16:15:54 »
Thanks everyone.

I'll try a couple of 19mm's I have and see what'll squeeze in there.  Thanks for the reminder about the shims.

Yes, I suspect that it has failed or at least want to eliminate it as a variable in my starting & running issues.
Greg R.
Washington, DC
W113 1967 230SL (auto, 250SL motor)
E24 M635
E38 740i sport
S3 Spider Veloce
ex-E32 735i, ex-E24 635CSi turbo, ex-1965 Falcon Futura convertible (301W H.O. transplant)

ja17

  • Full Member
  • Platinum
  • ******
  • USA, OH, Blacklick
  • Posts: 7308
Re: Barometric compensator (BC) removal quick questions
« Reply #5 on: December 02, 2019, 17:05:43 »
When the baro fails, the system usually goes lean.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

Greg R.

  • Associate Member
  • Junior Level
  • *
  • USA, DC, WASHINGTON
  • Posts: 24
Re: Barometric compensator (BC) removal quick questions
« Reply #6 on: December 07, 2019, 22:26:05 »
Thanks again, all.

I removed the BC and confirmed that it is kaput. 

-Greg
Greg R.
Washington, DC
W113 1967 230SL (auto, 250SL motor)
E24 M635
E38 740i sport
S3 Spider Veloce
ex-E32 735i, ex-E24 635CSi turbo, ex-1965 Falcon Futura convertible (301W H.O. transplant)