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73 eldorado exhaust manifold

Started by scott n, April 14, 2010, 10:34:09 AM

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scott n

My 73 Edlorado has a cracked left (drivers side) exhaust manifold. I can either replace it or have it repaired. In either case it will have to come off, although one person has said that the weld repair could be made with the manifold still on the car. I don't know if that is a good idea. Any thoughts?
I am very aprehensive about getting the manifold off without breaking the studs. All I know is to start soaking the studs with penetrating oil to lessen the chances. Does anyone have any other advice on removing/replacing the manifold?

Thanks

EAM 17806

#1
SCOTT!  If you can get those nuts loose without breaking them I would definitley replace the manifold because to try and weld it may be more of a problem since it would be difficult to verify any further cracks on the lower side of the manifold.  Give John Gately a call at 1-617-445-3300 to get a good used one, if he has one, and he'll treat you right plus give you some good ideas on how to take the cracked one off or whether you should weld it or not.  He's a quality guy.  EAM
Ev Marabian

1976 Cadillac Coupe DeVille, 1989 Chevrolet Caprice Classic, 1990 Pontiac Bonneville and 1996 Buick Skylark

35-709

Don't try to weld it on the car!  As I believe EAM was trying to point out, if you weld it on the car you cannot be certain you have gotten all of the crack.  Once off a good welder can fix it although you will see the repair.  Getting it off will be the challenge.  A 50/50 mix of Acetone and Automatic Transmission Fluid in a manual squirter makes the best penetrant there is.
Geoff N.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

TJ Hopland

They can be welded by someone that knows how and has the tools but I am not sure that it can be properly done on the car and like others mention you may not even have access to all the crack(s).  The cast welding I have seen involves an oven to control the heating and cooling of the part.

Dont just put a pipe on the wrench and lean on it.  Thats a sure way to break off stuck bolts.  You want to rock them gently back and fourth and try and work in the penetrant in.  As they loosen you will be able to turn them farther and farther till they come out.  If it does not seem like they are going to come out and you do not want to remove the head (or engine) the next best thing is to get a cutting torch and remove the heads of the stuck bolts.  This may damage the manifold but since its cracked anyway....  This will allow you to remove the manifold and leave the studs sticking out of the head.  You can then clamp a vise grip on the stud and use the torch to heat the area and now get penetrant direct into the threads.  You go back to the rocking method and they will come out.  You then just need a thread chaser to clean up the threads and you are ready to go back together.   If the bolts break off at the head you are pretty much stuck with drilling which even in the eldo on that side with decent access is quite a pain.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Kevin Bielinski #13320


i had the same thing happen on my '70 back in the '90's. Most likely those bolt heads will snap right off if you attempt to loosen them. I cut the exhaust studs and removed the heads and manifolds as a unit. Everything was disassembled at the machine shop. A new manifold was used. Don't wast your time trying to weld that busted manifold. Mine came off in three pieces from three cracks
CLC Western Regions Vice President
1970 Coupe Deville
1973 Miller Meteor 3 Way
1976 Series 75 Sedan
1988 Flower Car
1971 Lincoln Mark III
1984 Lincoln Town Car
1989 Lincoln Town Car Signature Series
2001 Lincoln Krystal Hearse

Past Vehicles
1971 Chevy Impala
1973 Chevy Monte Carlo
1973 Mercury Capri
1986 Lincoln Town Car
1996 Mercury Grand Marquis
1983 Buick LeSabre Limited