Fair price for motor mount replacement on a 68

[metalblessing]

Can anyone help me figure out what a fair cost is to have a shop replace motor mounts on a 472 in a 68 Cadillac Hearse? Just pretend its a fleetwood, same engine. I dont have the equipment (mainly jacks) to do this and I will likely need to have a shop do the work, I just have no idea what to expect money-wise, and I dont want to get gouged again.

[Scot Minesinger]

All you need is a floor jack, a block of wood and the wrenches/sockets.  It is not difficult except getting to the nuts on engine mount bolts.  I would do this yourself, because half the posts on this forum are about botched mechanical work.  Although this is simple in theory, it is easy to mess it up by someone who does not care.  You see an impact wrench will not fit.

The bolts are fine thread 3/8", long.  If these are rusted beyond practical re-use the shop will use something else rather than ordering them on Fastenol, waiting the day or two and installing.  A careless mechanic will damage the fule pump and then you will hear "these old cars...", any statement following this line is usually a lie.  I bought my Cadillac with the idea of hiring out the work 13 years ago, and after a couple years of this I do everything myself now that is possible.   

A floor jack, rather than a bumper jack is the price of admission for this old car hobby, and most auto parts stores sell them - get a good one.  BTW it is even easier if you use an engine crane because then there is more room to work, but an engine crane although so darn handy and inexpensive, is a little more advanced on the tools you should own to support your classic car list.

Good luck!

[Scot Minesinger]

The price I would expect to pay is about 4 hours worth of work to do it right (first time, read manual, all hand tools, difficult access) plus parts, so probably under $500 in our area.

[metalblessing]

I've never used a floor jack before. Is it safe to use if all I have to work in is an inclined driveway? I just want to make sure I dont end up crushing myself. It looks like there are some available for $50 or so. Not sure if theres a particular kind I need or not. And do I put the block of wood on top of the jack and lift under the oil pan? Thats what I saw on another youtube video.

Also is this the correct part? And there are 3 correct?

https://www.partsgeek.com/catalog/1968/cadillac/fleetwood/engine_mechanical/engine_mount.html

[gkhashem]

Are you just replacing the motor mounts?

Why I ask is I had someone replace them on my 1970 GMC truck when I put on a new oil pan gasket and replaced the front cover gasket and timing chain. When he did that he removed all bolts and lifted the engine to get at the oil pan gasket. So since we were at it we replaced the motor mounts too.

When he did it I was helping and it was no fun getting the bolts all lined up again since they were all removed to lift the engine.

So would you remove one at a time as to keep the engine aligned with the bolt holes?? Also on a 1968 can you remove the oil pan without lifting the engine? If not should you consider replacing the oil pan gasket while you are at it?

["Cadillac Kid" Greg Surfas 15364]

Blake
A knowledgeable mechanic should this no more than an hour per mount. You are correct there are 3. The 2 motor mounts and the transmission mount.
Greg Surfas

[Scot Minesinger]

If all you have to work on is an inclined driveway, it may not be a good idea to make this your first floor jack use.  You really have to know your physics and be experienced to work a jack on an incline, and the directions will prohibit this. 

Buy the factory shop manual, and they will tell you how to do the job.  This is VERY IMPORTANT for this and all other work.

Essentially the job for front two mounts is raise the car so you can get underneath it with jack stands.  The back transmission mount remains in place.  Remove engine mount to frame nuts.  Remove fan shroud (and maybe some other items cannot remember all details.  with block of wood on bottom of oil pan and floor jack under block of wood, raise engine up until engine mount bolts clear frame.  Remove the engine mounts and replace them.  Lower engine back down.  There are pins that guide it into place.  Install fan shroud and nuts back on frame to engine mount bolts.  Check everything and test drive.  The transmission mount is same principle and a little easier.

Good luck, and maybe find a level place to do the job at your friend's house on a nice Saturday afternoon.

[Jay Friedman]

I've never done this on a '68 (in fact, have never worked on a '68 at all), but have changed the motor mounts on my '49.  All I can say is that in my opinion on a '49 it would be dangerous to do this by merely supporting the motor from underneath with a floor jack. 

The reason is that both of the 2 mounts in the front of the motor must be detached and the motor raised couple of inches so the mount bolts clear the mount brackets on the frame.  At the same time it is best to loosen the nuts holding the bolts that attach the mount on the transmission so as not to strain the rear mount when the motor is raised.  As such, with just a block of wood on a floor jack the motor is what might be called "out of control" and could possibly tilt in one direction or another with disastrous results.  This problem would even be worse on an incline.  My solution--and on this I respectfully disagree with Scot--is that it's important to use an engine crane to raise the motor, since the motor would remain much more stable. 

Another consideration when raising the motor is to not strain the radiator hoses, fuel lines, linkage, control rods and other parts that are connected between the motor and the rest of the car.  Some of these will have to be dis-connected while others can remain in place.   

I wrote a Self Starter article on how I did this some years ago on my '49, which may or may not be relevant to doing the job on a '68, but I think I have a copy somewhere. 

[Scot Minesinger]

Jay,

All good points and with all due respect, the procedure I recited is in the shop manual and I have changed motor mounts on a 1965, 1968, 1970 (three), 1972, and 1975 Cadillacs in strict accordance with the FSM.  Supporting the motor under the oil pan with trans mount as a hinge point, raising engine about 1.5 inches is OK and does not strain the rubber fuel lines if they were properly installed (and they will pull off the metal lines if they are - fuel pump is right next to mounts and you will see it).

[metalblessing]

Thanks for all the information. I found a local place that works on classics and set an appointment ONLY to have them checked and quoted.

Now the reason I was asking about my motor mounts is because I had developed a tapping/clicking sound from my engine and I couldnt figure out what it was, some people had said it was probably my motor mounts, and since my engine shakes anyway it made sense.

Well yesterday I was poking around under hood with the car off, trying to make sense of what could be making the sound, when my hand bumped a cable and I heard the click sound. I nudged the cable again a few times and heard the sound. Followed the cable and it was my AC Relay. Previously I had unplugged the AC relay since not only does my AC not work but the connector is melted. Apparently the connector had managed to shimmy its way back onto one of the contacts (the wrong contact) and each time it wiggled it would intermittently make a connection and activate the relay, making a "click" sound.

I am VERY glad to have found this, but I'm still going to have my mounts checked Friday anyways because its an old car and I havent checked them yet anyway.

[Scot Minesinger]

The issue with a 50 year old classic even with no/low mileage is rubber fails due in part due to age, temperature and use (emphasis on age).  Most likely every rubber component that is original should be replaced to provide a like new, perfect mechanical condition.  Your timing chain if original should be replaced as well.  The upper control arm bushing in front seem to fail first.  The rubber mounts for the engine in front may be serviceable, but replacement is advised.  The urgency for rubber part replacement is not immediate, and can be managed over time (next two years or so).  This will prevent break downs and poor drive ability.

Again, I cannot emphasize enough to buy the Factor Shop Manual, and I see them on e-bay for $40 or so - get a used one, not the reprints or disks, you want good info., not a pretty book.  Going thru this manual would tell you in short order that the engine mount failures gneerally do not produce a click sound.  Shoot from the hip type mechanical advise is to be avoided (however, this forum is like that because it is very difficult to diagnose over the internet).

You huge problem with mechanics I found is they are unwilling to read.  When I first got my Cadillac in 2005, I would copy a page out of the FSM and highlight the sentence or diagram they needed to make sure was followed and they had a 100% failure to read and follow result.  You will be surprised how much better your work could be than many professional mechanics if you read the manual and follow it. 

In fairness to the mechanics it is very difficult to earn a profit on a classic car, because a low cost wait three days part is required that is tying up a bay because it cannot be driven, which can kill thousands of dollars of revenue and it needs to get out the door by any means possible, which is a conflict of interest for our classics.

[Jay Friedman]

Scot,

If the FSM says it should be done with a support under the motor in those '60s and '70s model years, then that is the way it should be done.   The '49 FSM doesn't deal with motor mount replacement and I have no experience with Cadillacs later than the '50s.

I used an engine crane on my '49 following the advice of Jack Hoffman and other CLCers who are club techs for the earlier years.  I now own one, but engine cranes that knock down (come apart) for transport can be rented from tool rental firms here in Georgia, so it is relatively easy to obtain one to use for a single repair project. 

Removing and installing motor mounts has its ironies, since it's a 5 minute job with the motor out of the car, and a major task with the motor installed.

I agree with you about many mechanics being reluctant to read FSMs and that we are better off working on them ourselves.  The limiting factor for me is old age, which is starting to cramp my style when it comes to climbing under the car. 

I also agree that there is little profit to be made professionally working on old cars.  A restoration shop in my area went out of business for that reason.