How To Loosen An Overtightened Inner CV Joint?

[coollx]

I'm working my way through the steps to remove the engine and trans in my car and am having a lot of trouble loosening the cv joint to transmission axle flange bolts on one side.

The side I'm having trouble with has what appears to be a newer or replacement axle assembly and the 6 bolts were really tightened a lot by whoever installed them....certainly much more than the recommended 30 ftlbs. So much so that a 3/8" breaker bar with 8" extension won't easily break them lose without probably rounded out the hex head of the bolt.

I'm thinking about using some heat on the axle flange to see if that will make a difference before I go to more extreme measures.

Since I've never had one of these apart before I'm wondering if the axle flange is the only part that the 6 bolts thread into?

Is it ok to use some heat on the flange, or is there another way?

Thanks

[Oh Haha]

A little heat is ok but you'll probably end up burning the rubber boot. That's ok if you plan to replace them anyway. (Good idea if you aren't sure when they were done or the are torn up.)

Try soaking the bolts in PB Blaster or Kroil for a few days. Also, be sure you are using the correct size socket on them. They are easily rounded off.

EDIT:Yes, they only bolt into the axle flange.

[Jim Sims]

I don't believe you need heat and if used it may end up damaging adjacent rubber in the boot or in the transmission output flange lip seal. Ensure the hex wrenching features in the bolt heads are completely clean of debris so the hex bit will fully and deeply seat. Use a hex bit in good condition with new sharp hex corners; grind the bit down if necessary to get to non-rounded corners. Apply inward pressure to keep the bit seated in the bolt head while turning - sometimes it is helpful to have a second person; one keeping the bit seated and the other pulling on the breaker bar handle. Use a breaker bar with a longer handle (~18") for more leverage; usually 3/8" breaker bars have handles that are too short for this task. If the screws were overtightened they should be replaced as they are likely stretched. If the wrenching feature in a bolt "rounds out" one can sometimes gain purchase by tapping in a torx or triple square bit but this usually ruins the bit used. There is also room to use a good pair of visegrips firmly clamped on the outside of the head of the bolt to remove it.

[911st]

Get a hand held impact wrench that you hit a hammer. Not sure but Sears may have these or try Post tools. I think they are about $15 and you need a 1/2" drive socket style Allen to go with it.

If you end up striping it out, it you will have to drill out the head.

I think the Might spray some PB on the opposite side of the Allen bolt from the head and let it set. If you apply heat, do so on the back side, not near the rubber boot.

[euro911sc]

Why not just cut the head off... dremel would do it just fine. When all the bolts are off the CV should just slip off the stuck bolt...

Or...

Is this the last one left?? If it is the last one left the angle on the shaft may be tweeking the whole CV and increasing the torque required to remove the one bolt...

Best regards,

Michael

[kodioneill]

heat won't work on the head end of the bolt. you may start a fire. pull on the parking brake hard. use 1/2 inch breaker bar with a short 8mm allen make sure it's clean like the previous poster said. it will come out.

[coollx]

My car has 8mm bolts with a 6mm hex head. Now that I've got some good responses I think my plan today will be to spray the end of the bolts thread where it peeks through the axle flange, then give the bolt a small direct on whack with a socket bit on the end of an extension and try again. If that doesn't work I'll try heat on the threaded area coming through the flange. If that doesn't do it I guess its time to cut the heads off.

By the way, its all 6 bolts from the passenger side that won't budge.

One last question. If I have to cut all the heads off, is there enough movement in the rest of the axle assembly while still attached at the outer CV joint to pull the inner CV joint out and away from what remains of the studs on the flange?

[911st]

There is play and worth a try with the CV rotated with the bolt up. However, my guess is you will have to remove the other end.

[euro911sc]

All six... hrmnnn... if it were 1 then there is enough movement... but all six I'm not sure as I think you might run into trouble on the lower side. Still, you could move the CV out of the way as far as you can and then use the cutoff wheel to cut between the CV and the flange... would be a real PITA. I think cutting off all the heads should be your last resort. I'm interesed in how this goes so let us know your methods and results!

-Michael

[cubby911T]

I had similar trouble with pressure plate bolts recently, which are also of the allen head style. My final solution was to cut a slot across the bolt head and use an "air chisel" type of fitting on my impact wrench to break the bolts free. Worked like a champ.

[coollx]

Here is an update.

HEAT IS YOUR FRIEND!

I sprayed PB Blaster on the ends of each bolt where the threads come through the transmission axle flange a couple of times over the last couple of days. Then gave the head of each of the six bolts a few whacks but the bolts would not budge. I used a breaker bar and extension totaling about 16". Because my car has the smaller 8mm bolts with 6mm hex heads a longer bar is no help since the increased leverage only serves to hasten the small bit rounding the inside of the bolt head.

So then it was time for the torch. I carefully rotated the axle so the bolt I was working on was pointing straight down and therefore furthest away from the starter wiring and in a spot where I had greater control.

The result was that I was able to remove each of the six bolts without rounding the inside of any bolt heads or cutting off any bolt heads or without breaking anything.

I must tell you that even with heat some of the bolts required two or three applications before the bolt loosened up. In those cases, I would apply the heat then quickly try to loosen the bolt. When a bolt required more than one application of heat you could feel the bolt turn slightly with a audible creak then stop and not budge. Then I would repeat applying heat and trying to loosen until the bolt finally broke loose.

So far, while working to do my first engine and tranmission drop, loosening these bolts was the second most difficult job I've faced. The first was loosening the fitting connecting the engine hard oil line with the flexible hose going to the thermostat. I did this without damaging either line but it required making two
3 1/2' long steel extension bars for my 10" and 15" adjustable wrenches in order to have enough leverage to brake the fitting loose without the end of the hard line moving.

I'm sure there will be other challenges along the way to my first engine drop. You guys will be the first to hear when I return for more advice.

This site is great and the only reason I decided to buy my 911.

Thanks for the help.

[Rusty Heap]

Breaker bars will tend to just twist off the bolt or strip the fastener.

A 3/8" butterfly air impact wrench is your friend.

[911st]

Heads up. There are special wrenches for oil lines.

It is to easy to bend a fitting a wrench that hole works off two surfaces.

[euro911sc]

After pulling the engine the first time in 25 years... its all easy after that!

-michael

[jhhaas]

Got stuck today dropping the motor. Everything is done except the tranny and engine mount bolts and, you guessed it, 1 CV bolt. I rounded it out, tired vice grips, PB Blaster, drilled out the bolt and broke the bolt extractor. It is crazy stuck. Guess I'll try some heat tomorrow.

[livetopedal]

I used a twist socket to release my stripped CV bolts. Worked like a charm. Check it out:
10pc. Twist Socket Kit at National Tool Warehouse

[Quinlan]

Keep in mind that there are some people (who aren't very forward-thinking) who actually put loctite on cv bolts. If they have committed this sin, heat may be your only alternative - cutting the head off the bolt could REALLY put a fly in the ointment.

[blpetry]

Originally Posted by livetopedal

I used a twist socket to release my stripped CV bolts. Worked like a charm. Check it out:
10pc. Twist Socket Kit at National Tool Warehouse

^^^^ X2.... works great

[jhhaas]

Originally Posted by blpetry

^^^^ X2.... works great

Just bought a set. Will try it out tonight. Fingers crossed

[safe]

Originally Posted by Quinlan

Keep in mind that there are some people (who aren't very forward-thinking) who actually put loctite on cv bolts. If they have committed this sin, heat may be your only alternative - cutting the head off the bolt could REALLY put a fly in the ointment.

Loctite is not a bad idea. A loose drive shaft can do som damage, let alone leave you stranded...