1972 Eldorado engine mounts replacement

[Christophe2m6]

Hi guys!
It’s my first topic here!

My name is Chris from France and I own a 1986 Pontiac Fiero 173ci, a 1969 Oldsmobile Cutlass Supreme 350ci and since a month, a 1972 Eldorado Convertible 500ci!

I would need some help for replacing the motor mounts.
I checked in the Service Manual, and it seems that there are 3 support mounts.

One at the front of the engine, and two on each side of the trans, right?

I found this part, and would know if I have to order 3x the same part?

https://www.rockauto.com/fr/catalog/cadillac,1972,eldorado,8.2l+500cid+v8,1025862,engine,motor+mount,5552

Do you have any tips/advices to help me?

Thanks a lot for your help!
Chris

[The Tassie Devil(le)]

G'day Chris,

Welcome to the ownership of a Cadillac, especially a '72 Eldorado.

The pictures mounts are not for the '72, but a later model which mounts the engine with two mounts at the front.

The Eldorado has a single mount fitted under the front of the engine under a steel frame that is a two-piece part, that rises up to attach to the side of the engine.

The picture shows the steel support, (blue) and you can just see the mount under and behind the crankshaft pulleys.

From what I have heard, these mounts are not easily obtained as replacements, and I had to settle for a used one when I found that mine was broken.

The rear mounts fit to the rear support bracket.   In the pictures, they are upside down as I took the picture whilst it was in the parts washer.

Bruce.

[Glen]

This looks like the correct one.  But the rubber is oil soaked and needs to be remolded.  Steel Rubber will do that for $120 each.  The ones I had done look good. 

https://ebay.us/jCNiDo

You don’t need all of that, just the part pictured below. 

[Christophe2m6]

Thanks a lot for your help Bruce and Glen!

Now I see exactely what I need and of which part we're talking about!
So the best would be to send my engine mount to Steele Rubber and let it rebuilt for $141.40 (price raised a bit!  )!


What would be your advices to remove the part without taking the engine out of the car?
From what I've read in the Service Manual, you can raise the car, put a jack under the crankshat pulley, then lower the car slowly and taking care of the steel, rubber hoses...

Thanks again for your help!

[Glen]

I have pulled the front mount out of my 68 ELDO by raising the engine a bit after unbolting the mount.  There are two bolts to the frame and one bolt each for the arms the go up to the block.  I would not lift on the crank pully, it seems a little to fragile.  IIRC I put padding under the front f the oil pan and jacked up the engine there.  You don’t have to lift it much. 

[Christophe2m6]

Thanks Glen!

Got an answer from Steele Rubber!
Will remove my mount and let it rebuilt!

Thanks again for your help!

[Christophe2m6]

Hi Guys!
Back with my engine mount replacement...

I finally took the time today to (try to) remove the front engine mount!

I unbolted the 2 engine mount, then both arms bolts...
Put a pad on a jack and raised the engine a little bit...
The engine raised but the car came with it... so the mount did not come out from the frame...

What did I wrong...?
Is it because of the Axle shaft? Transmission mounts that need to be unbolted?

Thanks a lot for your help!!

[Scot Minesinger]

The frame and engine mount should separate, it may need a love tap to break it lose.  I replaced the front mount too on a 1972 Eldorado.  Make sure you seal up the front cover well, an oil leak is what can take them out.  I used the compressor (top two threaded 5/16" threads) to lift engine with an engine crane rather than to jack it up from below.  Some times when you block it, you do not notice it rests on frame too and everything gets lifted up.  I removed bolts from front mount and frame, not engine and mount. 

BTW, yes had to get it rebuilt at steel rubber - you may want to buy a core and send that in.  I never remove something critical to my car being able to be driven and send it out for re-build because you might not get it back.  I sent a core in and switched the original for the re-build core after it came back.  Then I sent the original front mount and had it re-built as a nice spare.

[Glen]

You need to lift the engine more than a little bit.  As you lift the engine the weight is removed form the suspension and the frame follows the engine for a distance. 

[TJ Hopland]

I suspect Glen may be correct in that you were just taking weight off the the suspension so you need to go higher.   Are you doing this with an engine hoist or trying to jack it from below?   I use a hoist for this sort of thing. 

I have not done the -72 style but do you have to loosen the rear mounts so you don't damage those and have room to pivot things?

[Christophe2m6]

Thanks guys for all your help!
I’ll try to lift higher to see if I get it high enough to loosen it!

Same question concerning the trans mounts.
Do I have to loosen them to remove the front mount?

Thanks again!!

[Roger Zimmermann]

I would do it. I don't know how flexible they still are, why take a chance?

[Christophe2m6]

Hi guys!!

Got my engine mount back from Steele Rubber and they really did a great job!!

But they removed the studs and now I’m missing the two bolts needed to bolt on the mount to the frame.

Could you please help me and tell me the size of the two bolts I need (yellow arrows on the attached pic)?

Thanks again for your help!

[Christophe2m6]

Any help?

Thanks

[The Tassie Devil(le)]

I will see if I can dig out my spare in the morning and advise further.   I am off to bed now.

Bruce.

[Scot Minesinger]

That is not right part.  The front mount is a center unit and you can see it with hood open.  Make sure you have a Cadillac Factory Shop manual (on e-bay for $40 or so).  That will give you a picture.  Usually a front engine cover oil leak takes them out.  If you replace it seal up the front of the engine well too.

Since you likely have a front engine cover oil leak, replace the timing chain if it is original.

I replaced a 1972 front engine mount and went thru this already.  I think they have to be rebuilt, no new ones around.

[Christophe2m6]

That is not right part.  The front mount is a center unit and you can see it with hood open.  Make sure you have a Cadillac Factory Shop manual (on e-bay for $40 or so).  That will give you a picture.  Usually a front engine cover oil leak takes them out.  If you replace it seal up the front of the engine well too.

Since you likely have a front engine cover oil leak, replace the timing chain if it is original.

I replaced a 1972 front engine mount and went thru this already.  I think they have to be rebuilt, no new ones around.

Sorry but it’s actually the right part?
I removed my original front and central engine mount and sent it to Steele rubber to rebuilt it.
I have a Cadillac Service Manual.

[The Tassie Devil(le)]

I humbly apologise for my tardiness, but for the life of me, I cannot find it easily.   I will have to delve a lot deeper into my parts stash to dig it out.

Bruce.

[Christophe2m6]

Hi all!

Just to let you know that I finally found the engine mount bolts size!
Bolts are 7/16! 

I put the rebuilt mount on the car and everything is ok!!

Thanks a lot for your help!

[toukow]

Do the issues with replacing the motor mounts for this year of Eldorado extend to other years? I have a 76, and was intending on replacing them as part of replacing the timing chain. Rock Auto shows several model mounts available (some with interlocks, some without). Not sure which I need in that regard. Are the mounts readily available for the 76 year or is refurbishment of the old ones required as was done in this thread? Thanks, Dean