Tighten your diff bolts!

Just a friendly reminder to periodically tighten the hex bolts on your axels. Last night in the way to dinner my wife noticed a clunky sound. I took a look but couldn't see much in the dark and had the car towed home. I Ubered home and once sober I took a look today. Apparently I lost 2 bolts and the remaining 4 were finger tight on the rear right axel (outer bolts).

 

I remember a wise lambo mechanic telling me to always retighten all axel bolts with every service. He was right! And considering it takes 15 minutes to do, it's a no brainer. I suspect the previous owner failed to do so. Now I just have to wait to get the new bolts and I'll be good to go.

It's a good call! I've had my inner rear drive shaft bolts come loose. Luckily it hadn't bent or damaged the bolts, and I just re-fitted and torqued once inspected. I will be keeping a check one a year though.

 

Have you considered getting drilled bolts and tie-wiring them? They might work loose but they will never be more than a hair and can't fall out.

Sounds like they need some good old Loctite.

 

FYI for anyone needing the torque specs from the manual:

 

"Once the train power assembly has been installed, connect the rear drive shafts to the differential tightening the screws to the prescribed

tightening torque; drive shaft mounting screws: 88.0 Nm (which is 65 ft bs for us)"

 

"Install both front drive shafts and tighten the mounting screws to the prescribed tightening torque: drive shaft flange screws: 39.0 Nm (29 ft lbs)"

 

I have my car apart doing all kinds of maintenance and changing exhausts (yes, again), so this is a timely thing to check -- thanks!

Can someone please post a picture of what Cuhuba and Pmdw1 were talking about for freshman like me to understand? TIA

Good advice!

I had everyone come loose about 100 miles after a clutch job. Got lucky and didn't loose any bolts but all on drivers side were loose and axle popped out. Fixed it on the side of the road with my bare hands and drove home 1 mile.

 

Tighten them by lying on the garage floor with a good torque wrench. I was happy I had some mechanically skills that day.

Real good advice

Well i received the 2 bolts and backing plates I needed, total was only $70 shipped to my door. I went ahead and removed, applied red loctite, and torqued all 24 bolts to 65 lbs (thanks Stimpy). There were several that were definitely not tight at all.

 

According to my mechanic the left proximal shaft bolts are the most dangerous since when they come undone they have a tendency to shred the oil filter with massive oil loss and catastrophic engine failure! He has seen it happen and I believe him. He also said the front diff bolts almost never come loose.

 

I took pictures but can't seem to be able to upload them via iphone.

I checked mine. All nice and tight. None even a little bit loose.

 

It's a bit of an effort checking with one person. For the rear, you have to check 6 bolts * 4, and you have to hold the wheel from turning while you check each one. If you have another person, you could have them pull the hand brake for each check. My other person was sleeping.

 

If you find any lose bolts, I would highly recommend adding loctite. It's not normal for bolts like that to work themselves out. These half shafts are in just about every type of car on the road today, and you don't see this as a recommended service on any of them. Loctite will keep them in until you're ready to remove them.

I checked mine. All nice and tight. None even a little bit loose.

 

It's a bit of an effort checking with one person. For the rear, you have to check 6 bolts * 4, and you have to hold the wheel from turning while you check each one. If you have another person, you could have them pull the hand brake for each check. My other person was sleeping.

 

If you find any lose bolts, I would highly recommend adding loctite. It's not normal for bolts like that to work themselves out. These half shafts are in just about every type of car on the road today, and you don't see this as a recommended service on any of them. Loctite will keep them in until you're ready to remove them.

 

It is a little tricky as a one person job. I used a lock of wood to wedge between the wheel and the floor. I also use my kids to move the block of wood and hold in place. It's a character building experience for them

Well i received the 2 bolts and backing plates I needed, total was only $70 shipped to my door. I went ahead and removed, applied red loctite, and torqued all 24 bolts to 65 lbs (thanks Stimpy). There were several that were definitely not tight at all.

 

According to my mechanic the left proximal shaft bolts are the most dangerous since when they come undone they have a tendency to shred the oil filter with massive oil loss and catastrophic engine failure! He has seen it happen and I believe him. He also said the front diff bolts almost never come loose.

 

I took pictures but can't seem to be able to upload them via iphone.

 

Red Loctite will permanently adhere the bolt. It will take heat to get it out the next time. Blue is your friend for this type of hold.

 

Just a friendly reminder to periodically tighten the hex bolts on your axels. Last night in the way to dinner my wife noticed a clunky sound. I took a look but couldn't see much in the dark and had the car towed home. I Ubered home and once sober I took a look today. Apparently I lost 2 bolts and the remaining 4 were finger tight on the rear right axel (outer bolts).

 

I remember a wise lambo mechanic telling me to always retighten all axel bolts with every service. He was right! And considering it takes 15 minutes to do, it's a no brainer. I suspect the previous owner failed to do so. Now I just have to wait to get the new bolts and I'll be good to go.

 

Are these bolts in the picture was what you are referring Cuhuba? This is my 08 LP640, pic taking while it was getting the service done. All bolts are tight. There was a campaign in the past for these bolts if I'm not mistaking.

Are these bolts in the picture was what you are referring Cuhuba? This is my 08 LP640, pic taking while it was getting the service done. All bolts are tight. There was a campaign in the past for these bolts if I'm not mistaking.

 

Yes, those are the fronts and are smaller. The rear ones are the most likely to misbehave and use a 10 hex key

Thank you for verifying this Cuhuba

Are those on both ends of the half shaft? Hence the (6) bolts * 4? Haven't gone in for a closer inspection yet.

Are those on both ends of the half shaft? Hence the (6) bolts * 4? Haven't gone in for a closer inspection yet.

 

Yes. If you look at the rear shafts there are 6 bolts on the wheel end and 6 bolts on the transmission end for each side. Total of 24 bolts and each pair of bolts has a thin metal bracket linking them in pairs. All the rear bolts are the same.

 

BTW, my mechanic was absolutely on board with me using the red permanent loctite, because I did consider going with the less aggressive blue. These bolts are not supposed to be removed unless you are replacing a shaft, which with the typical low miles on these cars its hard to imagine when I would ever be in that position unless you are making way more power than stock.

 

Only time I have removed shafts on a car is to change gears on a muscle car. I doubt I will ever need to mess with the shafts on my LP.

 

I'm glad you guys are learning from my near disaster. It's a simple job that can save a whole lot of hurt, especially if the left bolts by the oil filter come undone.

cuhuba, you'll be removing those bolts any time the engine comes out, which is not that rare on these cars since the engine has to come out to change the clutch or do any work on the egear. Most other stuff can be done with the engine in.

 

I've used both the blue and red many times, and it's not like the red welds the metal together, you can still get them out pretty easily.

cuhuba, you'll be removing those bolts any time the engine comes out, which is not that rare on these cars since the engine has to come out to change the clutch or do any work on the egear. Most other stuff can be done with the engine in.

 

I've used both the blue and red many times, and it's not like the red welds the metal together, you can still get them out pretty easily.

 

Good point on the engine out! And agree, I've removed suspension and caliper parts with red loctite and aside from dropping the f bomb a couple of times they all come off.

Thanks for posting up this info.