I am stunned at the cost of these bolts.
can someone tell me what size and grade they are please.
Original Post
Replies sorted oldest to newest
Hello Rocky,
I have asked for the size and grade, they are just bolts, don't forget that we over here have to pay the queen her taxes the post office their handling charges, the revenue men their Value added Tax.
The bolts are special, but surely available from a local fastener company in the UK.
$12.5 per bolt is I think very expensive, BUT I could be wrong.
I have asked for the size and grade, they are just bolts, don't forget that we over here have to pay the queen her taxes the post office their handling charges, the revenue men their Value added Tax.
The bolts are special, but surely available from a local fastener company in the UK.
$12.5 per bolt is I think very expensive, BUT I could be wrong.
Peter,
Why don't you just drill the heads of the OEM bolts for safety wire?
Why don't you just drill the heads of the OEM bolts for safety wire?
I would suggest that you might not do that because the bolts are brittle and the heads are shearing off, not really backing off.
I believe the safety wire is a “belt and suspenders” situation.
The main point is to replace the bolts with ones that won’t fail under the shock loads on that ring gear.
Loctite, and safety wire are just gravy.
I believe the safety wire is a “belt and suspenders” situation.
The main point is to replace the bolts with ones that won’t fail under the shock loads on that ring gear.
Loctite, and safety wire are just gravy.
Well I am surprised that the grade and size of these bolts is a mystery.
I did send ZF in England a mail asking for the same info.
Had a reply that the box is so obsolete and they sold the rights to the Box years ago to an American outfit that went broke, so no help from that quarter.
The vendors prices are far from Uniform, I have 3 prices 66 from Hall and 125 and 145 from other vendors, will check that Halls are locking wire ones, I could just wait and get one of my bolts and check it when I do the job I suppose...mmm sounds like a plan!
I did send ZF in England a mail asking for the same info.
Had a reply that the box is so obsolete and they sold the rights to the Box years ago to an American outfit that went broke, so no help from that quarter.
The vendors prices are far from Uniform, I have 3 prices 66 from Hall and 125 and 145 from other vendors, will check that Halls are locking wire ones, I could just wait and get one of my bolts and check it when I do the job I suppose...mmm sounds like a plan!
Hi Peter -
I have my old one in my hand. I assumed someone had official specifications.
The bolts (the kind that fail) are marked "U 106" on the top of the head.
The bolts are:
M10 x 1.0
Shank Length is 21 mm (probably really 20 mm)
Head size is 15 mm (Socket Size)
The bolts have fluting on the bottom of the cap dig into the ring gear carrier. I can't recall if my new bolts did. I think I recall Bosswrench saying the fluting was ineffective against the hardened steel carrier.
Hope this helps you.
Rocky
I have my old one in my hand. I assumed someone had official specifications.
The bolts (the kind that fail) are marked "U 106" on the top of the head.
The bolts are:
M10 x 1.0
Shank Length is 21 mm (probably really 20 mm)
Head size is 15 mm (Socket Size)
The bolts have fluting on the bottom of the cap dig into the ring gear carrier. I can't recall if my new bolts did. I think I recall Bosswrench saying the fluting was ineffective against the hardened steel carrier.
Hope this helps you.
Rocky
Attachments
Images (1)
Peter,
Have you contacted ARP? I wonder if they know what the correct bolts are? Once you have an ARP part #, you could try Summit or Jeg’s, etc.
Have you contacted ARP? I wonder if they know what the correct bolts are? Once you have an ARP part #, you could try Summit or Jeg’s, etc.
Hi Peter -
Also remember there is a pretty good chance you will dick up the allen bolts that hold the differential housing together. This of course only applies if you don't have access to the special bearing puller tool for the side plate bearing races.
You can also avoid removing the allen screws of you do the safety wiring while the differential remains mounted in the housing (more limited access and constrained volume).
You should plan to remove / replace all of them (you can buy replacement allen screws at your local Ace hardware store).
You will also need the gasket set. Most of the vendors have them, including SACC and IPSCO (surprisingly!).
Rocky
The allen bolts I am talking about are the ones in this picture.... The light colored ones are stock - I replaced them with the black anodized ones shown. The object in picture is the top of the differential housing.
Also remember there is a pretty good chance you will dick up the allen bolts that hold the differential housing together. This of course only applies if you don't have access to the special bearing puller tool for the side plate bearing races.
You can also avoid removing the allen screws of you do the safety wiring while the differential remains mounted in the housing (more limited access and constrained volume).
You should plan to remove / replace all of them (you can buy replacement allen screws at your local Ace hardware store).
You will also need the gasket set. Most of the vendors have them, including SACC and IPSCO (surprisingly!).
Rocky
The allen bolts I am talking about are the ones in this picture.... The light colored ones are stock - I replaced them with the black anodized ones shown. The object in picture is the top of the differential housing.
Attachments
Images (1)
shearing off bolt heads leads me to believe you have a loose fitting housing set. a clean shear is a sign of possibly too hard of bolt (if there is such a thing)or too much torque at assy. if the heads are leaving a witness mark on the carrier then they are working. this is not to say the carrier is too hard for the bolts to hold. just the wrong application. I would stay with a grade 8 or Grade 9 standard style head and safety wire. grade 12 may be too brittle and cause the same problem. it has no elasticity. a short shoulder on the bolt never hurts and helps take up any slop in the holes. you may consider drilling additional holes and dowel pin it, peening the holes at the open ends of course.
Hi Tyler -
Shearing the ring gear bolts in the ZF is a longstanding problem with the stock ZF. It is not anything any of us have done - it's a flaw in the original Pantera ZF design.
Rocky
Shearing the ring gear bolts in the ZF is a longstanding problem with the stock ZF. It is not anything any of us have done - it's a flaw in the original Pantera ZF design.
Rocky
The diff carrier allens have cut-down heads for some reason. Combine short heads with too-tight torquing and decades soaking in hot oil while containing 300+ bhp, and it's no wonder the allen hexes strip while being removed. I've had some success at clamping a Vice-Grip pliers on the outside of a head while using a metric allen inside, using both simultaneously to untighten them. They remind me of the cheese-grade screws holding '60s Japanese motorcycles together: they hold OK but could not be removed without buggering up the cross-slots. Our salvation there was an impact screwdriver and a small hammer; maybe we ought to try that on ZF diff bolts.
As for the 10 ring gear bolts, the heads come off when the bolts relax from inadequate factory tightening or maybe overloading when we 'lean' on the engine too much. Slight loosening allows the bolt-head to impact the case sides; with over-hard bolts, it doesn't take many side-impacts to snap off a bolt head. Then there are only nine- each carrying slightly more load with one gone, until the cycle repeats. With broken-bolt ZFs, you can often see bolt-head tracks left in the cases. Of course, the real danger of broken ring-gear bolts is when a loose bolt head gets in between the ring and pinion gears while the engine is running. THAT can crack a ZF case like a walnut!
As for the 10 ring gear bolts, the heads come off when the bolts relax from inadequate factory tightening or maybe overloading when we 'lean' on the engine too much. Slight loosening allows the bolt-head to impact the case sides; with over-hard bolts, it doesn't take many side-impacts to snap off a bolt head. Then there are only nine- each carrying slightly more load with one gone, until the cycle repeats. With broken-bolt ZFs, you can often see bolt-head tracks left in the cases. Of course, the real danger of broken ring-gear bolts is when a loose bolt head gets in between the ring and pinion gears while the engine is running. THAT can crack a ZF case like a walnut!
Chuck thank you for the info, the job as you state isn't simple when you haven't done it before.
Your info is excellent and one can see that yourself and boss wrench have been around the block a bit with the ZF Box.
In light of the posts on this subject I will source my bolts from RBT as suggested, any get the gasket sets from them at the same time.
Not starting until winter, but I will be back for more help I'm certain.
Than you to everyone.
Your info is excellent and one can see that yourself and boss wrench have been around the block a bit with the ZF Box.
In light of the posts on this subject I will source my bolts from RBT as suggested, any get the gasket sets from them at the same time.
Not starting until winter, but I will be back for more help I'm certain.
Than you to everyone.