Apologies in advance because this may be kind of long...

So, back when I was a teenager (this would have been around '91-'92), Dad and I had the engine out of the 1500, and were swapping in a spare. I noticed that the forward mounting studs and nuts for the right front lever shock were larger than the rest, so I asked him about it. He told me a story about how he was driving down the road, when all of a sudden, the MGA decided to make an immediate and hard right turn on its own, which he was unable to stop. He spun a loop into the parking lot of a tavern, and miraculously didn't hit anything. Upon examination, he discovered that the studs for the right front shock absorber had pulled out of the frame.

He went into the tavern and used their phone to call my grandfather for help. Grandpa eventually showed up with a drill and other tools, and they ran an extension cord into the tavern for power. They repaired the car on the spot, and Dad drove it home that night. He said he never had reason to revisit the repaired area after that. This would have taken place sometime during the mid 60's. So at the time he was telling me about it, the repair had been good for around 25 years of semi-regular use (I last drove the car in 1999).

So, what I have, is the standard holes for 3/8" studs in the aft two locations, and oversize holes for 7/16" studs in the forward positions. And of course, a shock absorber with two holes drilled oversize. Here are some pictures... You can't really see the threads in the holes that well, but they are kind of ugly, and not exactly straight. As a matter of fact, they look a lot like they were threaded with hand tools, at night, by flashlight, in the parking lot of a tavern, by a couple of guys who were in a real hurry to get it done and get out of there.







So, now I have some decisions to make about what to do. The easiest answer would be to just put it back together the way it is with the oversize studs. But, I'm probably never going to have it stripped down to the bare frame again, or be able to turn it upside down, so I'll never again have the opportunity to make it right if I don't do it now. At least not as easily. And I'm not at all enamored of options such as welding up the holes, redrilling, and retapping. It's possible I could get a machine shop to make and install some special threaded inserts for the front. Not sure if the rears (the normal sized holes) were helicoiled, or what. The threads are pretty deep down in there and it's kind of hard to tell. And I want to make a repair that I can really trust, and that I won't have any reservations about, so what I really want to do is replace the tapped plate entirely, if it can be done.

From what I can tell, it looks like that area is a sandwich of three different layers of steel. There is the stamped front cross member section, and on top of that is resistance spot welded another layer of metal that the shock mounts on top of. And underneath the cross member, where the springs rest, is a thicker tapped plate that has the actual threaded holes in it. So, the holes for the studs go in for a ways before they hit the actual threads.

I'm pretty sure I can get in there with the frame inverted, and remove the welds for the tapping plate, using an air angle grinder with a cut-off wheel. And I'm also pretty sure that I have another front cross member that I can dissect to get a replacement tapping plate. My brother and I bought a parts car a few years back; the frame was very badly rusted so I eventually cut it up and only saved a few sections that I thought might be useful. If I still have it, it's currently buried under about 5 feet of snow in my back yard. Otherwise, it shouldn't be all that difficult to fabricate my own replacement plate if I have to.

I was just wondering if anybody else had any thoughts or suggestions, and whether anyone has heard of the shock mounts failing in this manner before? My dad was certain that the car had been raced before he bought it in '63, and he was never exactly easy on it, so it lived a pretty hard life. The swivel pin and one of the lower control arms on the other side were bent also, so it must have taken a hit or two. Also, the oversize holes in the shock absorber body itself are not an issue because I have extra shocks that I can have overhauled instead of the altered one.



Edited 1 time(s). Last edit at 03/25/2012 07:30AM by Oxide.

I had a similar problem when restoring my MKII. Two of the stud hole were stripped. I drill them out and tapped to 7/16 threads. I then found studs that were 7/16 cours on one end and 3/8 nfc on the other end. Its been that way since 1975.

---

Gil

The story is better than the fix.


I'd leave it. Get your dad and head out to the nearest tavern!

Dad's been gone for 12 years, and I don't drink, so there you go... I'd be more inclined to leave it as-is if the threads in the frame looked a little better. And considering what could have happened the first time they gave out, I'd rather just be sure.

Another question I forgot to ask; any experience or problems reported with the current crop of replacement studs for this application that are available from Moss, et al? I've grown kind of leery of repro hardware since I snapped a new head stud when torquing it down (ended up using the ARP kit as a result).

I like the tavern-fix story and would thus be tempted to leave it. The down side is that any replacement shock would have to be drilled out and that might make them worthless as rebuildable cores.

If you cannot find a stepped stud perhaps a thread insert would work?

---

Eric Russell ~ Mebane, NC
1960 MGA, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100

It is a good story. But I can still tell the story, even if I fix the frame. And I'll have pictures along with a messed up shock should I need to prove it for some reason.


That's a distinct possibility. MSC has something that should work for $1.62 each. It would certainly be easier than doing a plate transplant.



Edited 1 time(s). Last edit at 03/25/2012 09:03AM by Oxide.

You can use heli-coils to repair it. You'll have to check, but it may be that all you have to do is screw the heli-coil into the threads you already have and you're done.

JIM in NH

That is a great story.

When I did my car I found welsh plugs made of nickels from 1962 and 1966.

I left them that way.

Cheers,
Christopher

No-go on Helicoils, as the threads are different pitch, and the re-thread is to large. Best bet is thick wall threaded inserts.

The MSC parts should work, http://McMaster-Carr also has the required inserts, 94165A455 or 90245A074, and you can use standard drill and tap for installation.

---

Barney Gaylord
1958 MGA with an attitude - http://MGAguru.com
Notice: - Do not leave a PM for me on the forum server. Send any private message to my personal e-mail address barneymg@mgaguru.com

Bit of an update... Leaving the existing repair in place, or installing the threaded inserts, are both courses of action with a lot of merit. But, since this is MG restoration and not MG repair, I'm having a go at making it like it was when it left the factory. The only real way to accomplish that, is to remove the tapped plate from the cross member, and replace it with one that isn't stripped out. As of a couple weeks ago, the snow in my backyard melted enough so that I could retrieve the donor cross member. When I scrapped the frame, I cut off anything with useful looking bracketry and saved it, which turns out to have been among my better decisions. Here is the cross member in all of its rusty glory:



And here is the plate that needs to be removed. Note the 4 short welds holding it in place. There is a fifth weld on the back edge that is not accessible. These are not structural welds; they are only there to hold the plate in place until the shock is installed, at which time the studs bear the load of holding the sandwich together.



Cutting the welds. I was able to get the outer welds with the air grinder, but I had to finish the inboard welds with a Dremel tool with an angle drive due to not enough clearance. I could have done it all with the Dremel, but it would have taken longer, and if I'd had a shorter mandrel for the air tool it could have done the whole thing too. I was able to do it without doing any significant damage to the cross member (the cut off wheels barely marked it in a few places), so I now know that I can repeat the same process on my frame to remove the damaged plate. The purpose of this exercise was twofold; to obtain an undamaged plate, and to verify the process. Otherwise it would be back to the inserts.



Next picture is the plate removed from the cross member. I threaded a couple of used studs back into the holes and smacked them with a hammer in order to break what was left of the welds after grinding. After removing the studs, I threaded a regular bolt into one of the outboard holes from the bottom, and got under it with a pry bar and pried the end of the plate up, and then knocked it back down with the hammer. Did that a couple of times, and the 5th weld that was not accessible with the grinder gave way. It (like the others) wasn't much of a weld, and the cross member will never miss it once the repair is done.



Implements of destruction:



Here is the plate deburred, media blasted, threads chased, and primed with weld-through primer on the side facing the cross member (only):



Next step is to repeat the extraction process on my frame. Now that I know I can do it without messing up the cross member, I wouldn't necessarily have needed a donor frame, since it would be simple enough to make a new piece out of plate stock. I've also been mulling over an idea in my head for restoring the holes in the shock mounting surface (upper plate of the sandwich). Welding up the holes will be simple enough, and if I can remove that plate from the donor cross member, I should be able to use it as a drilling guide to make sure the holes are properly located. Then the tapped plate can be bolted in place, and the actual welding should be anti-climactic.

Like you, that would have bugged me for the rest of time. Glad to see you're able to make a real restoration rather than a rigged-up repair.

If you weld up the holes in the cross-member, can't you just use the (replacement) shock as a drilling guide? I'm assuming you'll be replacing the shock since it was drilled out also.

Very nice work, you went above and beyond what a lot of folks would have done.

if you weld up the holes, make a cardstock template before you do so that you can locate them later on - you want the holes correctly lined up with everything else, not just the shock body. Also, the tapping plate you just pulled should work as a dandy hole finding template from the bottom, since it probably only goes in one way and should be tight. Are the top plate holes through-holes, or are they also threaded? I think they're just through - holes, in which case you won't have to worry about threading them to line up with the threads in the tapping plate. I was worried that the tapping plate was in place and then they were tapped at the same time, which would be harder.

Great write-up - thanks!

I replaced the studs with the grade 8 bolt kit from Moss and am very satisfied with the quality of the hardware I received. Also makes it easier to remove the shock with the body installed, if necessary.

JIM in NH

"Like you, that would have bugged me for the rest of time."

I wish that I was that sort of guy, 'cept I'm not.


If you weren't returning everything to stock, think it would be possible to drill out the threads, run some correct length bolts up through the holes and weld the bolt heads to the inside of that plate, then tack the plate in place? Wondering because my frame really doesn't have any threads left on the shock mounts at all. Seems like a bolt and welded head would hold up forever.

Just through bolting them - even without welding - would probably last forever, provided you can get to the underside easily enough to either insert the bolts or start the nuts. Would be a PITA if you ever had to take it apart later on.

JIM in NH

"Would be a PITA if you ever had to take it apart later on."

Yeah, you're right. I would be for sure.



Edited 1 time(s). Last edit at 05/05/2012 01:57PM by TeamEvil.

I could. But I've also got the rest of the donor crossmember to hack up and use as a drill guide, and it also has the holes for the upper coil spring retainer, so I can use more hardware for bolting the guide in place, for a more positive alignment than from using just the other two shock mount holes.


They are through holes only.


Nope. The underside of the plate has to remain flat, since that is where the top of the coil spring rests. No bolt heads allowed. For what it's worth, if you can get the plates out of your frame, it shouldn't be all that difficult to make new ones, or have them made. Or you can do like I did, and extract them from a scrapped frame.

I sent this thread link to my uncle, and this was his reply:

Ah ha - I wasn't picturing the coil springs! That is why the Moss bolts are so short - duh - obvious now. I was wishing they were longer and therefor easier to start threading in, but I guess I am just not paying attention.

JIM in NH

You know... given how the "simple" new exhaust install is going, that does not surprise me one bit.

Just a couple of abused threads, and at least there aren't busted studs in there. Probably won't even have to helicoil them like I did for my A. No biggie. It is simple enough; it's just that sometimes simple things are also hard. Now the spark plug issue with your truck, that is a real booger. What an idiotic design!