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Violent shaking in my 48 Super

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A lot has been ruled out or worked on. The torque tube is straight forward. No carrier bearing. One u-joint behind the transmission. I suspect the u-joint was inspected. That leaves the pinion gears. If a shim has broken then there will be problems. Lets hope the shim clears up the shaking.

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Willie, thanks for the update on my comments about a rear U-joint on 48s vs. 58s!

From the pic I thought they were similar.

 

Bernie….. just what year is that pic from…?  cause it looks a whole lot like my pile of parts from the 58 Roadie….!

 

Dang, tho…it sounds like a u joint kinda problem to me from all that's gone down so far!

 

can't wait for the final resolution!

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The picture I posted is from my 1960  Electra. It developed an annoying slight squeak when driving at low speeds and, with the rear end raised on the pumpkin I traced it to inside the torque tube with a long screwdriver for listening. I got a helper and we rolled the rear end out. One internal u-joint had a cap with no roller bearing left inside. Everything else was fine, easily a $250 job. But, adding in the Imron paint, glass beaded wheels, new tires, fabricated steel brake lines with the coil spring guard, new rear brake hose,, refurbishing the original undercoating, new shocks, and new exhaust.... as long as we we under there.... I think I managed to bump it up to $4500.

 

Back to the currently broken car, defining violent reminds me of the time we ran a US Navy Destroyer onto the coral in Lauderdale.After a thorough diver's inspection things looked OK until we wound her up to 2/3 speed with me batting burners on the saturated side of a standard shift M-type boiler. THAT was violent shaking.

 

There are a bunch of things to try with it reassembled. Putting a tire between the bumper and a tree with a couple of guys lying on their belly watching and using listening probes while someone "makes the car dance" comes to mind. Maybe a little dyno time, but trees are easier to find. The spark plug idea is good and things as untenable as a burned through ignition rotor shorting to the shaft can play in. A vacuum gauge taped to the windshield might indicate a whole other problem.

 

I think I touched on the nature of the failure to repair in an earlier post. Can the mechanic play a good game of pool? It seems the world is lacking in good pool playing logic these days.

Bernie

Edited by 60FlatTop (see edit history)

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Hi Guys,

Wish I had good news, but...mechanic called late today. After adding a thicker shim to the gears in the differential and adding fluid to the rear shocks, it shakes as badly as it always has. The only two things that have not been removed are the pinion between the differential and torque tube and also the torque tube has not been removed. The items below have been replaced or checked.

Clutch disk- rebuilt

Pressure plate replaced

Flywheel sent out and resurfaced

Pilot bearing replaced

Synchronizer drum replaced

Cluster gear replaced

Reverse idler gear replaced

Front and rear cluster gear shaft bearings replaced

Torque ball inspected and passed

Torque ball seal replaced

U joint inspected and passed

Alignment checked and passed

Rear shocks checked and topped off with fluid

Rear end gears inspected and thicker shim added to reduce slop

Rear axle seals replaced

Thrust pad replaced and re shimmed

Motor mounts inspected and passed

Alignment of torque tube checked and passed

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In the repair manual, does it show a carrier bearing inside the torque tube?    The only other spot to check is the pinion propeller shaft bearing.  This will require the torque tube to be disassembled.  

Edited by avgwarhawk (see edit history)
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Up to now we've assumed the shaking is clutch back drive line related.  How about taking the hood off and taking it for an observation spin.  Perhaps a rider can see if the engine is stable or shaking too.  If the engine appears stable then you know it's not up there.  If not then I think you need to go back to the motor mounts and be sure they are properly attached to the frame and engine.  I'd be looking for cracked welds, broken rivets, or torn bases holding the mounts to the frame.

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Up to now we've assumed the shaking is clutch back drive line related.  How about taking the hood off and taking it for an observation spin.  Perhaps a rider can see if the engine is stable or shaking too.  If the engine appears stable then you know it's not up there.  If not then I think you need to go back to the motor mounts and be sure they are properly attached to the frame and engine.  I'd be looking for cracked welds, broken rivets, or torn bases holding the mounts to the frame.

As bad as the shaking is described; The engine is likely to be shaking, where ever the root is 

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Clutch chatter, once fully engaged, it is ok. Stuff is moving around and affecting the clutch linkage. As the engine torques over, angles change and clutch linkage and engagement cannot be controlled. I suspect you could feel the clutch pedal pulsing also.

 

I would check crankshaft end play just for grins, 1/8" end play might cause problems.

Edited by TexasJohn55 (see edit history)

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No kidding, two guys on their belly looking under and the car against a tree, shaking like hell. If it sounds too crude have them wear Snap On or Mac jackets.

 

Curious now, how does it take off in second?

Bernie

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Chris,

It only shakes under load at take off. I was able to drive the car through all three gears and once you're moving, there is no vibration what so ever. When I say violent shaking, I mean shake the teeth out of your head shaking. I tried feathering the clutch, starting out in second, etc. shake is so bad, you can barely get the car moving

 

 

No kidding, two guys on their belly looking under and the car against a tree, shaking like hell. If it sounds too crude have them wear Snap On or Mac jackets.

 

Curious now, how does it take off in second?

Bernie

 

 

It shakes like a hound dog sh---ing peach seeds!  I bet if you raised the hood and watched, you would see the engine flopping like a fish when trying to take off.

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It shakes like a hound dog sh---ing peach seeds!  I bet if you raised the hood and watched, you would see the engine flopping like a fish when trying to take off.

 But you will only see it for a second because standing in front of a car taking off is short lived.  :lol:

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 But you will only see it for a second because standing in front of a car taking off is short lived.  :lol:

 

That's what the tree is for!

 

None of you guys have ever burned oil off a clutch plate that way?

 

OK, here's the money maker and how you win at pool. There are two ways to service a Buick with a torque tube. Roll 'er out front under, which is my preferred way; or, the flat rate way, disconnect the shocks and Port-A-Power the rear end back enough to get room. Now out of the eighteen jobs, who pushed it back and bent the springs and tore up all the rubber mounts? "Not I" said the mechanic. Could have been decades ago.

 

It's peach pits up here. The seeds are inside the pits and pass as easily as a rearend rolls out from under a Buick.

 

I'm reminded of servicing hydraulic windows on a Cadillac some years back. The owner was emphatic about showing me a car that worked correctly. You should have seen his face when he saw how they worked correctly. His wife even mentioned how impressed he was. I told her "With ******'s money and my patience there is nothing we can't do." She even smiled.

Bernie

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That's what the tree is for!

 

None of you guys have ever burned oil off a clutch plate that way?

 

OK, here's the money maker and how you win at pool. There are two ways to service a Buick with a torque tube. Roll 'er out front under, which is my preferred way; or, the flat rate way, disconnect the shocks and Port-A-Power the rear end back enough to get room. Now out of the eighteen jobs, who pushed it back and bent the springs and tore up all the rubber mounts? "Not I" said the mechanic. Could have been decades ago.

 

It's peach pits up here. The seeds are inside the pits and pass as easily as a rearend rolls out from under a Buick.

 

I'm reminded of servicing hydraulic windows on a Cadillac some years back. The owner was emphatic about showing me a car that worked correctly. You should have seen his face when he saw how they worked correctly. His wife even mentioned how impressed he was. I told her "With ******'s money and my patience there is nothing we can't do." She even smiled.

Bernie

 

Never burned off oil on the clutch that way.   I use tire chocks.   This is how I would check manual cars for bad motor mounts.  Does not take much for the torque to lift the engine off it's broken mount when the wheels are blocked with chocks.  

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But you will only see it for a second because standing in front of a car taking off is short lived. :lol:

The '48 doesn't have an alligator hood as yours and mine does.

A '48 opens from either side, hinged on the opposite side of tbe opening,

Or, if one pulls the hood relase for both sides, the hood can be removed by two folks...

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James, yes. The clutch is all the way out, if you can get it to that point before the car shakes apart

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 But you will only see it for a second because standing in front of a car taking off is short lived.  :lol:

 

Chris, I didn't tell you where to stand. Us country boys know better than to stand in front.

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Question. What are the three or four set screws for on the pinion gear cover right behind the torque tube? Do those ever need adjusting?

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Question. What are the three or four set screws for on the pinion gear cover right behind the torque tube? Do those ever need adjusting?

 

I do not believe there are any adjust screws on the torque tubes.  The entire housing is a bolt together affair.  

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