Damn lock nut
Damn lock nut
This is the one thing stopping me from getting into the meat of my tranny rebuild.
This locknut (on the big driveshaft in pic) measures 1.61" / 41mm across the flats, and according to the FSM is torqued to 100-150ft-lb. I used a dremel to carefully remove the staked portion, it's very clear. I tried using a screwdriver at a corner to hammer it loose, but no dice. It's been soaked in PB, but not heated since I don't know what I'm heating exactly. The nut surface itself is only 1/4" tall. Mazda SST is a socket wrench that is over a foot long and covers the driveshaft.
So yesterday I ordered a 1-5/8 crowfoot flare wrench that fits well enough. Problem is, it's 12pt flare style and this wrench just pops off when I put a little torque on it - the flare just bends open and pop off it comes. I thought it would be perfect, but the nut is too short for it to grab well.
Anyone have the SST wrench? Or other ideas? (Monday I have an appt at the <gasp> dealer to have them remove it for me.) I'd love to cut it off, but I can't afford to damage the driveshaft or clutch hub ($200/ea).
Dave
This locknut (on the big driveshaft in pic) measures 1.61" / 41mm across the flats, and according to the FSM is torqued to 100-150ft-lb. I used a dremel to carefully remove the staked portion, it's very clear. I tried using a screwdriver at a corner to hammer it loose, but no dice. It's been soaked in PB, but not heated since I don't know what I'm heating exactly. The nut surface itself is only 1/4" tall. Mazda SST is a socket wrench that is over a foot long and covers the driveshaft.
So yesterday I ordered a 1-5/8 crowfoot flare wrench that fits well enough. Problem is, it's 12pt flare style and this wrench just pops off when I put a little torque on it - the flare just bends open and pop off it comes. I thought it would be perfect, but the nut is too short for it to grab well.
Anyone have the SST wrench? Or other ideas? (Monday I have an appt at the <gasp> dealer to have them remove it for me.) I'd love to cut it off, but I can't afford to damage the driveshaft or clutch hub ($200/ea).
Dave
Only thing I can think of is drilling a shallow hole on one of the "points" of the nut to anchor a large punch to try to hammer it around. I think the FSM says to replace the nut anyway and it's probably not expensive.
Weird Cat Man
Joined: Aug 2001
Posts: 2,868
Likes: 3
From: A pale blue dot
Is that the nut that holds 5th gear on? I think I used a large chisel with a heavy hammer (mini-sledge) and banged it off. You need the chisel to bite into the nut... Is the driveshaft securely held? Helps to have it really steady so it doesn't move and kill your momentum.
Yeah, it's secured nice and tight with a rag in the gears. Vice grips - yeah right, not this one. It's like a mini flywheel nut.
Did anyone try heating it? (I don't want to cook the adjacent bearings, but I dunno)
I tried giving her 'ell with the screwdriver and hammer, I guess I'll have to resort to a chisel or digging a deeper notch for the chisel to grip onto. Someone else suggested I double-check it's not reverse threaded - boy would that **** me off if it were. Naturally it gets replaced - Ray Crowe gave me the bill $492 (!!)
I'll try again tomorrow am.
Dave
Did anyone try heating it? (I don't want to cook the adjacent bearings, but I dunno)
I tried giving her 'ell with the screwdriver and hammer, I guess I'll have to resort to a chisel or digging a deeper notch for the chisel to grip onto. Someone else suggested I double-check it's not reverse threaded - boy would that **** me off if it were. Naturally it gets replaced - Ray Crowe gave me the bill $492 (!!)
I'll try again tomorrow am.
Dave
Last edited by dgeesaman; Dec 29, 2004 at 09:10 PM.
Senior Member
Joined: Dec 2003
Posts: 260
Likes: 0
From: Stanford, CA
Hello-
Hmm... I do have some other ideas. They may not work, or may be totally inapplicable, but I'll throw them out and maybe one will spark an idea :-). I've never pulled apart a Mazda tranny before, but have done several other ones. That said, here's a few tricks...
First, can you get the shaft out of the case, even with gears and whatnot assembled on it? If so, take it out. Then, you can use a table vise to grab onto the nut very cleanly. Grab the gear assembly and turn. Or, if you have a core, dead tranny lying around, you may be able to scavenge "helper" parts from it. For example, I once used an extra one of the extra Porsche 915 reverse gears to weld a socket onto. Then, I could use the splines inside of it to grab onto the mainshaft and apply torque with a breaker bar or torque wrench with the nut in a vise... it's like vise grips, only it doesn't booger everything up and you can apply torque correctly :-). It was like my own SST!
If you can't get the thing out of the case, then can you at least move the shift forks independently? One trick used to disassemble some transmissions is to force two shift forks into different gears at the same time. This locks the shafts to each other - they'll never rotate (the only speed that's the same in two different gears is 0mph :-). Then, whatever tricks you do to loosen the nut (i.e. impact, chisels, etc.), the shafts will stay put for you - much better than some rags in the gears.
The last idea I have is to buy a nice, big 1 5/8" socket, then modify it. If you can bore a hole in the middle of the socket large enough to fit the shaft through, then weld a pipe onto the socket, you have your very own super-uber-mega-deep socket :-). You can weld another socket on top of the pipe to give you a place to put a 1/2" drive breaker bar or whatever into. If you plan to do any welding with sockets, I recommend purchasing impact sockets. Since they aren't plated, they can be welded with relative ease.
Hopefully some of this will help... although I wouldn't be surprised if none of it does :-). Let us know how it turns out.
Take care,
Shad
Hmm... I do have some other ideas. They may not work, or may be totally inapplicable, but I'll throw them out and maybe one will spark an idea :-). I've never pulled apart a Mazda tranny before, but have done several other ones. That said, here's a few tricks...
First, can you get the shaft out of the case, even with gears and whatnot assembled on it? If so, take it out. Then, you can use a table vise to grab onto the nut very cleanly. Grab the gear assembly and turn. Or, if you have a core, dead tranny lying around, you may be able to scavenge "helper" parts from it. For example, I once used an extra one of the extra Porsche 915 reverse gears to weld a socket onto. Then, I could use the splines inside of it to grab onto the mainshaft and apply torque with a breaker bar or torque wrench with the nut in a vise... it's like vise grips, only it doesn't booger everything up and you can apply torque correctly :-). It was like my own SST!
If you can't get the thing out of the case, then can you at least move the shift forks independently? One trick used to disassemble some transmissions is to force two shift forks into different gears at the same time. This locks the shafts to each other - they'll never rotate (the only speed that's the same in two different gears is 0mph :-). Then, whatever tricks you do to loosen the nut (i.e. impact, chisels, etc.), the shafts will stay put for you - much better than some rags in the gears.
The last idea I have is to buy a nice, big 1 5/8" socket, then modify it. If you can bore a hole in the middle of the socket large enough to fit the shaft through, then weld a pipe onto the socket, you have your very own super-uber-mega-deep socket :-). You can weld another socket on top of the pipe to give you a place to put a 1/2" drive breaker bar or whatever into. If you plan to do any welding with sockets, I recommend purchasing impact sockets. Since they aren't plated, they can be welded with relative ease.
Hopefully some of this will help... although I wouldn't be surprised if none of it does :-). Let us know how it turns out.
Take care,
Shad
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Weird Cat Man
Joined: Aug 2001
Posts: 2,868
Likes: 3
From: A pale blue dot
Originally Posted by dgeesaman
Yeah, it's secured nice and tight with a rag in the gears. Vice grips - yeah right, not this one. It's like a mini flywheel nut.
Dave
Dave
Junior Member
Joined: Dec 2004
Posts: 36
Likes: 0
From: Waterford, MI
Since you have a dremel handy. Use a cutting wheel and make a slot as deep and as long as you can in the face of the nut perpendicular to the staked portion. That should give you a good seat for a cold chisel. When you smack the chisel real hard - CCW?, my bet is that the nut will fracture inside the slot, or the nut will turn before it cracks. If not then try to wedge, if you can, the slot to make it crack. If not, then cut another slot perpendicular to the first and as close to the shaft as you can get and hit it again as before. It should darn well give right at that staked part - it's the weak point.
Another thought would be a sink wrench - but have now idea how you'd get enough leaverage to turn 100+ ft-lb
Another thought would be a sink wrench - but have now idea how you'd get enough leaverage to turn 100+ ft-lb
Things like huge adjustable wrenches, etc don't work because the locknut is short and the outer diameter of the clutch hub sits up a bit. Breaking/hammering/cutting it off is fine, but I will still need to retighten the new one.
Brian, this is the second locknut, that doesn't need removed simply to do a 5th gear synchro. I will attempt to remove the interlock pieces or roll pins and use the 1st/4th gear trick. I thought about it before, but figured the rags were secure enough and much easier.
I'm going to check on a few things:
- if it's left-hand threaded
- how much it would cost to make an SST using 1.5" Sch 40 pipe and 41mm Deep Impact Socket (the socket is $20 from McMaster-Carr, but cutting it in half and welding in the pipe may be costly). I'll have to pay a shop to do the work.
- how much the SST (491243-465A) is
- if that local sdealership has the tool and will do the nut for me in reasonable time.
I'll let you all know what worked in the end. I already spent $30 on a wrench that didn't work.
Dave
Brian, this is the second locknut, that doesn't need removed simply to do a 5th gear synchro. I will attempt to remove the interlock pieces or roll pins and use the 1st/4th gear trick. I thought about it before, but figured the rags were secure enough and much easier.
I'm going to check on a few things:
- if it's left-hand threaded
- how much it would cost to make an SST using 1.5" Sch 40 pipe and 41mm Deep Impact Socket (the socket is $20 from McMaster-Carr, but cutting it in half and welding in the pipe may be costly). I'll have to pay a shop to do the work.
- how much the SST (491243-465A) is
- if that local sdealership has the tool and will do the nut for me in reasonable time.
I'll let you all know what worked in the end. I already spent $30 on a wrench that didn't work.
Dave
Last edited by dgeesaman; Dec 30, 2004 at 06:55 AM.
I Win!
The first time, I used the dremel only to remove the staked part of the nut and tried to torque it off.
More precise dremeling got me about 85% cut through the nut, leaving a little material at the bottom ID. I made the cut alongside the keyed portion of the shaft so I could get the dremel wheel in closer. It took patience like a brain surgeon to avoid nicking the shaft or clutch hub. A flathead screwdriver in the cut slot made for a nice pry point, and it finally cracked.
As Brian said, engaging two gears works much better than the rag trick. If you're only doing a fifth gear synchro, then stick with the rag trick b/c getting the roll pin back in might be a b*tch.
Mazda SST (# 491243-465A) can be bought from American Kowa Seiki (800-824-9655) for $92.71. It's basically a 41mm 6-point socket that is 15" deep. The local dealer did not have one, and the local transmission shops didn't have any such tools either.
For reassembly, I'm going to build an SST-like super deep socket. The 41mm McMaster-Carr socket cut in half + 14" of pipe welded in between should do the trick. I will make this available to anyone who needs it in the future for a very fair rental price. Details will be in my writeup when I'm done.
Dave
More precise dremeling got me about 85% cut through the nut, leaving a little material at the bottom ID. I made the cut alongside the keyed portion of the shaft so I could get the dremel wheel in closer. It took patience like a brain surgeon to avoid nicking the shaft or clutch hub. A flathead screwdriver in the cut slot made for a nice pry point, and it finally cracked.
As Brian said, engaging two gears works much better than the rag trick. If you're only doing a fifth gear synchro, then stick with the rag trick b/c getting the roll pin back in might be a b*tch.
Mazda SST (# 491243-465A) can be bought from American Kowa Seiki (800-824-9655) for $92.71. It's basically a 41mm 6-point socket that is 15" deep. The local dealer did not have one, and the local transmission shops didn't have any such tools either.
For reassembly, I'm going to build an SST-like super deep socket. The 41mm McMaster-Carr socket cut in half + 14" of pipe welded in between should do the trick. I will make this available to anyone who needs it in the future for a very fair rental price. Details will be in my writeup when I'm done.
Dave
Last edited by dgeesaman; Dec 30, 2004 at 12:29 PM.
Junior Member
Joined: Dec 2004
Posts: 36
Likes: 0
From: Waterford, MI
Originally Posted by dgeesaman
The first time, I used the dremel only to remove the staked part of the nut and tried to torque it off.
More precise dremeling got me about 85% cut through the nut, leaving a little material at the bottom ID. I made the cut alongside the keyed portion of the shaft so I could get the dremel wheel in closer. It took patience like a brain surgeon to avoid nicking the shaft or clutch hub. A flathead screwdriver in the cut slot made for a nice pry point, and it finally cracked.
As Brian said, engaging two gears works much better than the rag trick. If you're only doing a fifth gear synchro, then stick with the rag trick b/c getting the roll pin back in might be a b*tch.
Mazda SST (# 491243-465A) can be bought from American Kowa Seiki (800-824-9655) for $92.71. It's basically a 41mm 6-point socket that is 15" deep. The local dealer did not have one, and the local transmission shops didn't have any such tools either.
For reassembly, I'm going to build an SST-like super deep socket. The 41mm McMaster-Carr socket cut in half + 14" of pipe welded in between should do the trick. I will make this available to anyone who needs it in the future for a very fair rental price. Details will be in my writeup when I'm done.
Dave
More precise dremeling got me about 85% cut through the nut, leaving a little material at the bottom ID. I made the cut alongside the keyed portion of the shaft so I could get the dremel wheel in closer. It took patience like a brain surgeon to avoid nicking the shaft or clutch hub. A flathead screwdriver in the cut slot made for a nice pry point, and it finally cracked.
As Brian said, engaging two gears works much better than the rag trick. If you're only doing a fifth gear synchro, then stick with the rag trick b/c getting the roll pin back in might be a b*tch.
Mazda SST (# 491243-465A) can be bought from American Kowa Seiki (800-824-9655) for $92.71. It's basically a 41mm 6-point socket that is 15" deep. The local dealer did not have one, and the local transmission shops didn't have any such tools either.
For reassembly, I'm going to build an SST-like super deep socket. The 41mm McMaster-Carr socket cut in half + 14" of pipe welded in between should do the trick. I will make this available to anyone who needs it in the future for a very fair rental price. Details will be in my writeup when I'm done.
Dave
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