[Norseman50]

OK. I give.

What's the trick to removing the four bolts/nuts that hold the two rear prop shaft flanges together?

The nuts on the rear (differential) side do not have enough clearance between them and the pinion shield to get a box wrench over them.

On the front flange, there is not enough space between the bolt heads and the trunnion clevis ears to allow a box wrench or short socket to slide all the way down flush.

What's the deal? Am I supposed to loosen these bolts/nuts with only 13mm open ended wrenches and/or crescent wrenches or vice grips? I'm certain the use of those tools will only result in rounded head/nut points and busted knuckles (not to mention the fact that none of them will provide enough torque to actually un-seize the bolts).

How the @#*! do I get these apart?

P.S. Please ignore the dirty differential casing in the photo. I'll get to that later.

 

[Alfajay]

Yea, open-end wrenches. Quality wrenches won't damage your hardware. Vise-grips are a no-no, however.

 

[alfaparticle]

Yea, open-end wrenches. Quality wrenches won't damage your hardware

That's right. Good quality wrenches will usually have thicker jaws than cheap ones. I have a set of Proto combination wrenches for jobs like this.

 

[MNVXer]

I'm certain the use of those tools will only result in rounded head/nut points and busted knuckles (not to mention the fact that none of them will provide enough torque to actually un-seize the bolts).

I got mine off with open-ended wrench. The key for me was HEAT - I blasted these bolts with my torch, which incidentally has been used on suspension work for three of my cars, AND doubles as a creme brule torch in the kitchen during the "off season."

get a torch - it makes this work 10x easier.

 

[Norseman50]

I've got a little propane torch I use for sweating solder into copper plumbing joints. Is that what you're talking about?

How hot should I get the bolts? Red hot?

If I get the whole flange too hot won't I run the risk of damaging the differential seal?

 

[MNVXer]

I've got a little propane torch I use for sweating solder into copper plumbing joints. Is that what you're talking about?

How hot should I get the bolts? Red hot?

If I get the whole flange too hot won't I run the risk of damaging the differential seal?

This is what I use for my work:

Others may use mapp gas? I usually put 20-30 seconds of heat, more if things are really not moving. A few applications will tend to loosen really stuck bolts. I don't think I've ever made bolts glow - I don't believe this gas gets hot enough for that on these beefy suspension/drivetrain components.

As for the differential seal - I don't believe that you would damage it, unless you apply heat/flame directly to it. Mine was fine, but as with everything on the internet - take this with a grain of salt.

 

[Norseman50]

This is what I use for my work:

Others may use mapp gas? I usually put 20-30 seconds of heat, more if things are really not moving. A few applications will tend to loosen really stuck bolts. I don't think I've ever made bolts glow - I don't believe this gas gets hot enough for that on these beefy suspension/drivetrain components.

As for the differential seal - I don't believe that you would damage it, unless you apply heat/flame directly to it. Mine was fine, but as with everything on the internet - take this with a grain of salt.

Hi MNVXer,

Yup. That's the same little torch and nozzle that I have. Works great on soldering copper plumbing systems.

I'll use it and give your "heat" trick a try on those stubborn bolts/nuts. Probably give 'em a couple light taps with a hammer while I'm pullin' on the wrench too....

I'll let you know how it goes.

If all else fails, I guess I could try and carefully cut the bolts (or grind their heads) off.

Other than having 13mm heads, does anyone know the thread size/pitch in case I need to purchase replacements bolts?

Thanks again,

 

[alfaparticle]

They are special bolts.

 

[MNVXer]

They are special bolts.

If you're replacing the bolts, replace the nyloc nuts too and match them to what ever you can find that is the correct diameter and hardness.

The heat will work... the internet guarantees it.

 

[Alfajay]

How hot should I get the bolts? Red hot? If I get the whole flange too hot won't I run the risk of damaging the differential seal?

My first concern about heat would be annealing the nuts & bolts. As alfaparticle points out, the bolts are special - they're shoulder bolts. The nuts are 9mm fine threaded so would be tough to replace. I'd be hesitant to cook them.

Honestly, I've never had that much trouble with that hardware. Just use two open end wrenches, align them so that squeezing the two wrenches together loosens the nuts, and they're off. Reassemble with Loctite (since the self locking feature on the nuts will be worn out), torque to a setting of "real tight", and you're done.

 

[Stevew]

And another thing.

"P.S. Please ignore the dirty differential casing in the photo. I'll get to that later."

Upon very close examination, I was indeed able to see the vague outline of a differential in your picture .

I replaced the pinion seal on mine years ago to overcome a similar leakage issue but the problem returned and quickly frosted my diff in a new coating of grunge.

Last time I was under the car, I dropped the bottom diff cover (the gasket is sturdy) applied Mega Copper High Temp Silicone sealant to the gasket and all has been well for several months. Unfortunately, motor oil from the rear main and tranny fluid from a failing front seal continue to mist everything to the rear :-(. I'm not sure I can add the front main seal as a contributor to the mist, but maybe that's part of my problem as well.

All the best.

 

[MNVXer]

My first concern about heat would be annealing the nuts & bolts. As alfaparticle points out, the bolts are special - they're shoulder bolts. The nuts are 9mm fine threaded so would be tough to replace. I'd be hesitant to cook them.

Annealing the bolts? For real? I think you're over thinking this. You're not supposed to make the bolts glow red hot - just get some heat cool cycles to bust any oxidation present.

 

[AngloSpider]

Honestly, I've never had that much trouble with that hardware. Just use two open end wrenches, align them so that squeezing the two wrenches together loosens the nuts, and they're off. Reassemble with Loctite (since the self locking feature on the nuts will be worn out), torque to a setting of "real tight", and you're done.

+1 for this. I have done exactly the same on both my cars and not had a problem apart from a grazed knuckle

 

[MNVXer]

+1 for this. I have done exactly the same on both my cars and not had a problem apart from a grazed knuckle

Mine were impossible to remove when doing my driveline restore. Both the middle and rear sections were seized. I had to use heat to get those bolts loose.

Also, the flanges themselves were oxidized together (with the bolts removed) and I needed to whack the fudge out of it with a mallet. I was repaid with a surprise driveshaft to to midsection. It was funny.

Minnesota car.

 

[Norseman50]

MNXVer,

Did you replace the nylock nuts with new ones after you heated them? I'm concerned that even a small amount of torch time will melt the nylon and hinder their locking ability for re-use.

Where the heck can you get M9 bolts anyway, and are they M9-1.00 (fine thread) or M9-1.25 standard thread pitch?

 

[sloboy89]

MNXVer,

Did you replace the nylock nuts with new ones after you heated them? I'm concerned that even a small amount of torch time will melt the nylon and hinder their locking ability for re-use.

Where the heck can you get M9 bolts anyway, and are they M9-1.00 (fine thread) or M9-1.25 standard thread pitch?

I think they are available from Alfaholics.

Propshaft to axle bolt – 9mm | Classic Alfa Romeo spare parts and accessories

 

[AngloSpider]

ClassicAlfa lists them too GB033 PROPSHAFT BOLT (9 mm) - Classic Alfa

They state that they are for later cars with 9mm holes only.

£3.50 each is not cheap though...

 

[Alfajay]

Did you replace the nylock nuts with new ones after you heated them? I'm concerned that even a small amount of torch time will melt the nylon and hinder their locking ability for re-use.

You're right, heating nylock nuts is going to kill the locking function. But even if you don't heat them, the nylon wears out with use. Dunno how many cycles of disassembly-reassembly the nylon is good for (in aircraft the answer would be "one"), but on a 40 year old Alfa, the odds are good that the driveshaft has been apart several times.

Buying fresh nuts (as discussed in posts #16 & 17 above) would be one solution. But as I wrote in post # 10, applying blue Loctite is another way to re-use old hardware without worrying about it coming loose.

You do NOT want your driveshaft bolts coming loose!

 

[AngloSpider]

Good advice. Is blue loctite one that you can undo again without heat?

 

[ghnl]

Yes, blue Locktite can be disassembled with hand tools, red usually needs heat (or big tools...).