Hello

Replaced rear wheel hubs, VIDA says , tightening torque of the bolts( holding the hub) is 130Nm. While tightening them in, one head stripped. I can't get it in or off. What am I supposed to do?

PS - I could give the rest of the bolts only 90Nm. Do you think its dangerous?

 

Hmmm that is unfortunate. Sorry to hear. The bottom line of course is that 90 is significantly below 130 on a critical part so I would be inclined to address quickly.

Some questions to consider in taking this risk though:
1) is it a critical piece - yes
2) if you were to leave as is can you easily monitor over time so that you can fix before it becomes dangerous...not really
3) will more parts be damaged if it comes loose...yep
4) would I let a loved one drive it in its current condition?...not for more than a day or two.


Dont mess around. Get it done right. Look up some tricks online to get the stripped bolt out. Get new bolts from Volvo for a couple of bucks, get the correct tools to tighten up to spec. Piece of mind is priceless.

 

Thank you for your advice! I will do it
BTW too small room for getting the bolt out..lol

 

What is the bolt size ?

 

Hello, gstallons.

they are T50, the hubs are held by 4 bolts on each side.

 

I understand that is the head size , but the bolt size... e.g. 10mm or 12mm .
You can Google bolt / torque specs. charts on the internet to see if you are using the correct measure.
Also , you say "stripped" . Does this mean you have pulled the threads out of the mounting , threads pulled off of the fastener or the head of the fastener is damaged ?

 

Hello again, gstallon. Thank you for your contribution.

I believe it's 5/8 inch. I don't know the SAE grade of bolt.
And my head is stripped off. I'm not sure the rests are fine. How do you know the thread is damaged?

Assuming that it's SAE 2, 130Nm is required for 8/5-11 bolts. And for 1/2-20 bolts, 80Nm is required. If I tighten the 8/5-11 in 80Nm, do you think the clamping force will be the same as the one from 1/2-20?

 

Hmmmmm,
Can you post some pics ? The pics will give some idea of what to do next. I am pretty sure all the fasteners on Volvos are metric. The dimensions you are giving are somewhat USS or SAE .
I don't know if your fasteners are internal or external Torx.

 

Hello again gstallon
I forgot to take pictures.. but I came with the exact info.
Thread size of the 4 bolts are M14.

 

So remind us, why is it that you can't get the correct torque on the rest of the bolts again? If you could get the remaining three to 130Nm that would likely be adequate.

 

You will need to remove the bolts you feel are bad . sometimes you can apply heat from a torch to get the bolt head red hot . let it set for 1/2 minute and then it should have expanded enough to be removed . Believe me , this works

 

I would get a bolt extractor and get the sheared off bolt out, then replace all 4 with new bolts.

Using an extractor takes some patience, but its not that hard. If you have never used or seen one, it looks like a tapered drill bit with fluted groves running in a spiral, reverse thread. You drill a pilot hole down the middle of the sheared bolt, then insert and screw in the extractor counter clockwise. The reverse threads grab into the bolt and should spin it out. The key to success is using the correct size extractor, and that first pilot hole. The more perfectly centered it is the better the extractors work. I usually use a hardened punch to bang a dimple into the center, then drill a smaller pilot hole for the larger extractor drill size to follow.

Since it sheared off while you were putting it back in I'll bet it comes out easy. Its when they are rusted in place and shear off while you were trying to remove the bolt, those are a PITA to remove.

 

hello Pierre
I could only torque it, because I couldn't find enough room for it. I used factory scissor jack , lied on the floor and did it. I checked the torque to 100Nm, it didn't click.

 

Haha, thanks again.
BTW. The sheared bolt, the last torque I checked was 80Nm...shouldn't it be PITA anyway?

and also, how many room should I have to use those device? can I use it with normal wrench?

 

hello again (;
Yeah..I like the torch idea, to get it done I might have to detached the knuckle itself. There's too small room for that.

 

Can you not use an extension and maybe support the ratchet from underneath with a block of wood to make sure it is square? I'm having trouble visualizing why you don't have access or room to get the torque wrench in. A pic would really help here.

 

Sorry, have to ask... Are you sure you were reading the Nm scale on your torque wrench, and not the ft/lb? 90 ft/lb is close to 130Nm... and if you tried to force it up to 130 ft/lb (176 Nm), that could explain why the bolt head snapped, and why the others didn't want to go much past 90 ft/lb.

 

I'll make the picture! I jacked it up, but well. It's blocked by struts and knuckle itself, and it's far behind there for me.

 

Yes. It was Nm unfortunately.. It was corroded on the head( thankfully not the thread) on the time I took it off. When I took them in, I couldn't see clearly if I was doing right or not, I just knew I was trying hard to get them in and the ratchet seemed 'working'. Only to find out after a while, I was actually grinding the head

I went to a car shop and the mechanic found another bolt stripped too. He said he might have to deal with it when I change the hub for the next time.

I did some simple calculations, it seemed okay even though I couldnt torque it right. The mechanic said it too. So I'm gonna live with it i guess.. If I don't post here anymore, consider me dead on the highway xD