Down pipe stuck

[Khurram Darugar]

I was removing my downpipes yesterday and was a bit confounded when the they did'nt come off after i unscrewed the bolts.  I gave the downpipes a good wack with a mallot without any change.  

Further inspection revealed welding marks across the side of the header near the downpipe connection.  Im wondering whether the downpipe may be welded to the manifold using a drill and fill technique.  Pretty far fetched i know but that down pipe is really solid.

Does the downpipe slip off with a bit of wriggling?  

In case i need to replace the header ...  can one use a set from W108/W109 or other any other 2.8L mercedes?

Kay
68 280sl Euro LHD

[ja17]

Hello Kay,
Yes the front pipes should separate. Often times they do get stuck very tight. Heat from a torch is a good persuader, however jiggling and some blows with a hammer (on the front pipes only, since the headers are cast iron) should break them loose. If yours are welded, the this is definately a problem.

All Mercedes  250SE or 280SE, 108 and 109 chasis sedans with fuel injected engines  (1966 through 1971 ) with a six cylinder M129 0r M130 series  engies have the same headers.

These manifolds are very expensive new from Mercedes. Find a good donor car if you need them.

Joe Alexander
Blacklick, Ohio

[Malc]

Kay,
Agree with Joe about using heat, if you have access to an oxy-acetene torch so much the better. Suggest you try a few heat and cool cycles, but don't use water to cool it quickly as this may cause the casting to crack

If that fails....Cut the downpipes off about two inches down from the exhaust manifold (header)

Remove the manifold to the bench and then very carefully cut 180 degrees apart along the remaining pipe so you can split it. Maybe use an angle grinder very carefully.
Hopefully that way you can get the remains off without damaging the casting. I know it means you sacrifice your downpipes, but they are cheaper than a new manifold.

Good luck
Malc

[Khurram Darugar]

So this is'nt entirely unheard of.  I am scrapping the downpipes so if they get trashed thats ok.  
I think i'll take the header off, i dont trust myself with a torch in that area.  

I think i should be able to get another manifold from a 280se, if everything goes belly up,


so worse case i should be ok ...



Thanks Guys!

Kay

[Ben]

Mine were seized solid and I had to cut them off and then reweld whilst I ordered a new section.

Even when on the bench it was extremely difficult to seperate !

Regards,
Ben in Ireland.
'64 230SL 4sp.

[Naj ✝︎]

Hi, Kay,
Are the down pipes free at the bottom end?
I just had a new exhaust fitted to my 280. The guy loosened the manifolds at the head just to create some room to twist them either way, and that loosened them off.
Believe he did not use any heat.
naj

65 230SL
68 280SL

[Khurram Darugar]

Naj,
    They are free from the bottom i'll give them a twist to see if that helps but im not overly optimistic.  They did a guiter string impersonation when i hit them with the malot .....
Kay

[waqas]

Kay,
I'll second Naj's technique: once the bottom end was free, I went to the rear of the car and moved the rear muffler, alternating between side-side and up-down motion. The long muffler pipes provide a lot of torque at the header/downpipe interface. It took about 10-15mins of this to loosen them from the header. Good luck!

Waqas in Austin, Texas

[merrill]

Guys,
so, I had some time to kill today, so I started tearing down the motor on my sl.
the on the passenger side I am down to removing the exhaust headers.  everything else has been removed.  

and,of course, my exhaust down pipes will not come out of my exhaust manifolds.  

I read the post below and the replies,  and I have one question.


If I use the technique waqas referenced, should the manifolds be loose or tight?  I do not want to damage them.

thanks
matt

Matt
66 230 sl - "white"
78 300 D - Blue
98 C230

[Naj ✝︎]

Hey, Matt,

Since you're having the engine out, why not leave the manifolds in situ?

You will have enough room to twist them off the down pipes once the engine is out of the way (if needed).

naj

68 280SL

[merrill]

Naj,
now I am confused,  are you saying to pull the motor with the exhaust system still connected?  
I need to look and see where the down pipes are attached to the rest of the exhaust system.  If the connection is welded then I will need an alternate route.

thanks
matt

Matt
66 230 sl - "white"
78 300 D - Blue
98 C230

[Naj ✝︎]

Matt,

 

quote:now I am confused, are you saying to pull the motor with the exhaust system still connected?

Yes, or, if your remove the cyl. head, you still get more room to twist off the manifolds. I had to do that on my 230 but its more difficult with a RHD as the brake booster is also in the way.

naj



68 280SL

[bpossel]

 :?: Isnt the manifold attached to the head via studs and copper nuts?  Wont the studs break off if you twist, hammer on the manifold?
Just curious, because at some point I would like to remove mine and have them cleaned up.
Thanks,
  Bob

bpossel  (Memphis, TN.)
'71 280SL  /  '97 E320

[Naj ✝︎]

Bob,

 

quote:Isnt the manifold attached to the head via studs and copper nuts? Wont the studs break off if you twist, hammer on the manifold

I meant twisting the manifolds off after the cyl. head has also been taken off.

This will not apply to what you wish to do...

naj

68 280SL

[merrill]

so, I finally was able to get my exhaust down pipes separated from the exhaust manifolds.  Following the procedure below I did disconnect the exhaust system at all 3 connection points under the car and used the length of the system as leverage.  

after 4 days the rear header was finally free, and soon the whole  system was free.  Here are some pointers.

1. On the front manifold, take a permanent marker and mark where the exhaust enters the manifold.  this will help you find out if the connection is moving and which way. i.e.  left vs righ or top vs bottom.

I found that my front manifold had play left vs right but not top vs bottom.

2. If your system is stuck top to bottom, with the exhaust system loose, take a piece of wood and place it between the exhaust system and the bottom of the car as a lever,  that way when you grab the exhaust tips and rock the system up and down the joint is worked.

3.  IF one and 2 do not work,  I grabbed my exhaust tips, sat down behind the car, and shook the whole system up and down and amazingly the front header came unstuck.


For days I had sprayed pb blaster on the front manifold joint and had pulled the manifolds off the head and sprayed pb blaster into all of the manifolds so the lubricant could run down to the joint where the manifold and exhaust meet.

I also used a small torch to hed the front manifold joint,  I am unsure if the heating helped loosen the joint.

On my car the rear maniflod would not clear the head studs and the passenger side drain tube for the air system. I used a jack to lift the tranny / motor at the rear of the motor and then it just barely cleared.  I probably need new tranny mounts.

now on to the next step

matt

Matt
66 230 sl - "white"
78 300 D - Blue
98 C230