Question on motor mounts, 1971 fj40

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So here are some pics of my engine mounts. They don't look good and the mount on the drivers side is completely torqued because the frame is bent. There is also a pic of the type of mount I have in the front. The mount looks fine but it is square and 73fj40, you mentioned they should be round for an F engine, which is what I have (1971 truck).
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…and 2 pics of the bent frame and one of the truck….

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sproggy said:
Hmm, re-reading your post I am now under the impression that the three spacer screws on the end of the fingers have the same measurement, meaning the distance between the head that rests on the throw out bearing and where the stem enters the threaded hole on the finger, yes? Mine are not even, that's for sure. So, tomorrow I will have a go at it....Strangely, the shudder is not always the same. Sometimes it is barely there. The truck seems to be friendlier in reverse i.e. less shudder.
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Mine fingers are not tight against the throwout bearing when the clutch pedal is not depressed. With hand pressure pushing the finger away from the throwout bearing I try to get the gap as even as possible. The idea is the throwout bearing will make contact with the three fingers evenly. When it doesn't and one gets pressure first the even pressure on the clutch disc causes it to shudder.

Seeing your rear motor mounts I would not wait and address those right away as well.
 
Past, what do you think that means for my clutch set up, that the fingers always touching the throw out bearing? So I need to back off on all of those 3 screws to allow for a gap...if that would even happen? Weird.... As for the motor mounts, I would love to get them sorted but how to do that? It seems to me a huge job, since it's a bent frame that's causing the problems, though the passenger side mount I think I can get at and add new rubber, for what it's worth. I don't have the time or money, if it's even worth it, to undertake such a project. Unless I'm mistaken and there would be some easier way.

Mdsims, I wonder who changed the mounts in the front? Perhaps it was when the collision happened and the front mounts were destroyed and the owner at that time changed them. Looking at my pic, there doesn't appear to be any rubber in there! I'll have to check more closely. I bought this truck from an auto repair shop way back when and it had a HUGE at least 100 pound 12 inch high steel bumper with giant rubber cushions welded to the front end. They used it to push around old cars, apparently, so who knows the abuse it took?
 
That would explain a lot. Pushing junk cars would be a tough life. Hard to say what you should do. I would look for a new frame. Used ones can be had fairly cheap. That's the best way to solve the beat up frame and rust issues at the same time. Just my opinion and others here are exponentially more experienced than I am.
 
X2 on a better frame.

Replace the rear mounts, and start the hunt.

Repairing the frame will likely require removing the body. The route I took was to sandblast and paint a replacement frame, lift off the body with a cherry picker, roll the older frame and drive train from beneath it, Swap the suspension and axles to the newer frame, lift the motor/trans/T-case straight up, roll the new frame under it, then lift the body and roll the new frame (including axles, wheels, engine, etc) under it. I did it solo, and the actual swap could be done in a weekend. Prep was a ton more. In total it took closer to 100 hours to do the whole job... But I only had a small sandblaster and put about 5 coats of paint on it.
 
Yes, you guys are most likely correct. The front two rails up to the bumper are completely distorted as well and have been welded a few times already...and the back rail is rotting out especially under the passenger side leaf hanger. At the point of getting a new frame...I might just as well get a new body which is equally challenged. Since I don't have the money or time to do such things now or in the near future I will probably opt to try and repair at least the pass side mount (new rubbers) and keep my eye on that back rail. My buddy said he bought a new back rail online and that it was fairly easy to cut out the old one and weld in the new one so that would be an option at least for that problem. If the shudder turns out to be from the clutch and I can fix it, or perhaps new rubbers on that one motor mount fixes it, I will be pretty happy. Believe it or not, the truck still holds the road just fine and the drive train appears to all be in order. I won't plan on doing any heavy off-roading. Anybody else have clutch adjustment experience?
 
Yes you are perhaps correct. To be honest, I would feel badly for my current frame...sniff sniff. As messed up as it is, it's an old friend. I'm sure I would be happy as a clam once I got over the brief grieving period! I'm in Mass, by the way. I suppose I would have to get out of snow and salt country to get a good one, right? Actually, I live in Thailand and have seen a few real beaters over there and thought about trying to get one cheap but I figure getting parts would be a nightmare.
I will check out that thread. I have had my tub off 30 years or so ago and did a bunch of stuff, new harness, clutch, body mounts, headers, blah blah but for some reason some how didn't notice the messed up frame. Hmmm unless it wasn't there and I did the damage myself on some outing.....but I was young and dumb. In fact, I put all the bolts mixed together in a coffee can! I dread taking off the tub again but I think to have a bit more wisdom now that I'm older. I hope so.
 
sproggy said:
There is also a pic of the type of mount I have in the front. The mount looks fine but it is square and 73fj40, you mentioned they should be round for an F engine, which is what I have (1971 truck).
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Sproggy, my post stated, "The round ones can be replaced with square ones". Apparently, yours were.

By the way, looking at the photos, you really don't have any effective rear motor mounts. It looks like someone attempted to make up for deteriorated rear mounts with washers. It could be the bad rear mounts are contributing to your shuddering. You mentioned the shuddering isn't as bad in reverse, which means the torque exerted on the transfer case by the drive shaft is the opposite of forward gear, supporting the fact that bad rear mounts may be at least part of the problem.

Also, Coolerman's picture shows a triangular-shaped bracket that is the anchor point for the clutch linkage tensioning spring. This bracket is missing in your pictures.

You should consult a factory service manual on the proper method to adjust the clutch linkage AND adjusting the three fingers on the clutch plate. Flying by the seat of your pants is not the way to go..
 
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Don't bother working on the passenger rear mount if you're not gonna fix the driver's side. The driver is the torque side, and I would bet TWENTY TIMES more likely to be the source of your shudder.

In fact I wouldn't touch you clutch until you fix that mount.

If you loosen the bottoms of the two front mounts, there's a good chance you can line up at least one of the two rear mount holes. The driver's side one is what you're after.

Cut off your old bolt. Yeah headers complicate things. I've used socket combos and masking tape on a boxed end wrench inserted thru an adjacent hole. It will also help to remove the mounting tab from the bellhousing.
 
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In the worst one I had to fix at the shop, the passenger rear was off by almost a bolt width. I used a carbide cutter to open up the hole, then welded a flat washer over the center of the realigned hole.

Form follows function.

Best

Mark
 
73FJ40 said:
Sproggy, my post stated, "The round ones can be replaced with square ones". Apparently, yours were.

By the way, looking at the photos, you really don't have any effective rear motor mounts. It looks like someone attempted to make up for deteriorated rear mounts with washers. It could be the bad rear mounts are contributing to your shuddering. You mentioned the shuddering isn't as bad in reverse, which means the torque exerted on the transfer case by the drive shaft is the opposite of forward gear, supporting the fact that bad rear mounts may be at least part of the problem.

Also, Coolerman's picture shows a triangular-shaped bracket that is the anchor point for the clutch linkage tensioning spring. This bracket is missing in your pictures.

You should consult a factory service manual on the proper method to adjust the clutch linkage AND adjusting the three fingers on the clutch plate. Flying by the seat of your pants is not the way to go..
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Thanks so much for your help and observations. I DO have the triangular-shaped bracket, only it is mounted on the wrong side of the slave cylinder. You can see it poking out from the bottom in one of those pics. The slave is leaking and needs a rebuild, I gather, so that will be a good time to put the bracket in the proper place. Good eyes. My buddy who helped work on the truck with me 30 years ago says the washers are my doing…that certainly could be. I do have a couple service manuals I will look into about that clutch.

Gee, as we all know, once you start poking around on these old cruisers there is no end to the problems you find that need tinkering with, usually entailing a lot of money, skinned knuckles, cursing, and contorting your body into strange and uncomfortable positions.
 
65swb45 said:
Don't bother working on the passenger rear mount if you're not gonna fix the driver's side. The driver is the torque side, and I would bet TWENTY TIMES more likely to be the source of your shudder.

In fact I wouldn't touch you clutch until you fix that mount.

If you loosen the bottoms of the two front mounts, there's a good chance you can line up at least one of the two rear mount holes. The driver's side one is what you're after.

Cut off your old bolt. Yeah headers complicate things. I've used socket combos and masking tape on a boxed end wrench inserted thru an adjacent hole. It will also help to remove the mounting tab from the bellhousing.
Click to expand...

"…masking tape"? How was that used? And what is the mounting tab on the bellhousing? The problem with the drivers side mount is the bent frame. I tried to show it in my photos but it is not so clear. there is a rise in the frame where it buckled directly underneath the mounting pin causing the pin to tilt toward the outside of the frame. No way I can fix that without serious fabrication, IMO. Hopefully, I can at least get the nut off and some new rubbers on there, ditto for the pass. side. Though the whole alignment might still be less than true it would at least be tight and secure. Well, that's my theory.

Are the mounting pins/bolts available?

Your time and help is much appreciated, 65swb45. Thank you.
 
65swb45 said:
In the worst one I had to fix at the shop, the passenger rear was off by almost a bolt width. I used a carbide cutter to open up the hole, then welded a flat washer over the center of the realigned hole.

Form follows function.

Best

Mark
Click to expand...

Hi Mark, thanks for your input. How come the hole was off? Accident? Yeah, form follows function which is why my truck is jerry rigged left and right. I kind of like the improvisation, as long as it is safe and works. You did this work with the tub off, correct?
 
Amen. The rolling resto of my first cruiser required tinkering EVERY WEEK for the first two years. Took a bag of tools with me wherever I went. After two years of skinned knuckes, creative additions to the english language and more than one Rube Goldberg to get me thru all the deferred maintainance, Ruftoys ran flawlessly for the next two years, restoring my faith that owning an LC was more than just a circle jerk.

Having considered your situation overnight, I would go so far as to suggest building a new cradle for your passenger rear mount before I would consider straightening the frame...for your rig...under your particular circumstances.
 
sproggy said:
"…masking tape"? How was that used? And what is the mounting tab on the bellhousing? The problem with the drivers side mount is the bent frame. I tried to show it in my photos but it is not so clear. there is a rise in the frame where it buckled directly underneath the mounting pin causing the pin to tilt toward the outside of the frame. No way I can fix that without serious fabrication, IMO. Hopefully, I can at least get the nut off and some new rubbers on there, ditto for the pass. side. Though the whole alignment might still be less than true it would at least be tight and secure. Well, that's my theory.

Are the mounting pins/bolts available?

Your time and help is much appreciated, 65swb45. Thank you.
Click to expand...

The tab I referred to is the mounting bracket on the driver's side of the bellhousing that the motor mount bolt goes thru.
Why? Yours is far from the only rig to have engine mounting issues.
 
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