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PMOSSBERG wrote:
Glad you found the blank drums. For $41 each, I would go with that, rather than welding and redrilling old drums.
I agree with Paul on using new blank drums here. The old drums would be to thin to drill and tap without building up a welded boss on the backside. Due to the nature of the drum material (cast iron/cast steel?) welding can be difficult and may crack under pressure or cause drum warping because of localized welding heat. This is only my opinion, but is based on working in machine shops in one area or another all of my adult life. If someone brought this project into the shop I work now I would not do the weld method due to a liability issue, but would be more than happy to drill new blanks for you. If you do find a shop that would weld it would probably cost as much as the new blanks for the weld. You also may find the splined adapters may need to be bored if there is enough material to fit over the outer bearing boss and dust cap on the front. Take the project to a good local job shop machine shop and let them put their heads together to determine the most cost effective and safe way to make this work for you. I am not sure of the shop cost in your area, but here I would estimate all four drums drilled and tapped to correct bolt pattern at $100-$125.00 .Good luck with your project.
Newkitman’s source for non-logo VW hubcaps is in this thread:
PMOSSBERG2012-05-01 12:00:44
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
Thanks Mike, All who know me think I am overly cautious. I agree with you about your concerns, – especially about weakening the drum by welding and causing stress risers. It’ll be good and it’ll be safe when I finish else, I will just keep the old steel wheels and chalk this whole experiment up to experience. I do plan to get a used drum, drill and tap it to see how I like the wider stance that Ed mentions. Also, if there is any grinding to insure proper clearances, I’ll get smart on a $10 drum and still be able to drive my TD while head scratchin’. I will probably buy one front and one rear drum. I really have to keep a tight financial reign on this project as I’m retired and $200 here and $100 there is a lot for my budget. So far I have $300 spent before I even start the painting, mounting, adapting, new tires etc etc.
Go Roy! Hoping this will work. I might try it meself some day.
Mike: (and Roy:) (and everybody): The Triumph TR3 spline adapters will fit over the VW hubs, as I found out for myself a few months back. On the rear, you just have to bend the cotter pin. On the front, the outer lip on the grease caps will have to be ground off in order for them to seat.
$41 blank drums? That sounds like the way forward, if you’re not doing a front disc conversion. I like the discs but they, too, tend to widen your stance an inch or two. Discs and wires together would probably mean narrowing the beam–kiss another $300 goodbye.
edsnova2012-05-01 13:30:30
Royal in no way do I think you are being overly cautious when we are talking about a car doing 55mph and losing a wheel. Please dont think I am slamming your project in any way here as I like what you are attempting and am pulling for your success. I do think this is very doable, but may not be within the dollar range you are looking for. Project costs tend to snowball once you start for instance my recent conversion from wire wheel caps to smoothies with MG medallions. By the time I bought paint, caps ,medallions ,two new wheels as two of mine were very pitted, 5 tires unmounted /remounted and balanced and did all the work myself, I spent over $400.00.. a sum which in almost 35 years of husband wisdom decided my wife was better off not knowing. As for as cast material welding our shop will weld cast iron, but it is always in a not hazzard situation. A competent shop may look at your adapters and find it would be easier to turn the flange off and weld and machine a new flange concentric with the splines. I would think the adapters are steel and not a cast material making the welding much easier.Again good luck with this and keep posting as I and others are interested to see you complete it.
Speaking of wives, I have been shanghaied by mine today for a landscaping project. No problem since I am just waiting for my wheel package to arrive. This is good time to do the heavy duty thinking. Keep your comments coming, I’m listening.
Just talked to the guys at socalauto and here is the first wrinkle in my project: They only supply blank drums for the rear. ??? Huh? Go figger. Anybody have a link for fronts?
I’ve not been able to find blank front drums.
But CIP1 has 4×100 mm brake drums for front and rear.What is the bolt pattern on your adapters?PMOSSBERG2012-05-01 16:08:12
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
Royal I read that one guy does this by drilling and using press in studs pressed from the backside and lug nuts instead of tapping and using lug bolts. I dont know if this is a good idea without knowing the thickness of the area in the drum where the stud would press . If there is enough meat I dont see why it wouldnt work. As for tapping thickness most shops use a general rule of thread diameter for material thickness to be tapped (1/4-20 in 1/4 plate) . This would be the minimum.
PMOSSBERG wrote:I’ve not been able to find blank front drums.But CIP1 has 4×100 mm brake drums for front and rear.What is the bolt pattern on your adapters?Paul you may be on to something here. 130mm translates to 5.118 and 100mm is 3.937. That is .590 per side on a bolt circle. From the looks of the hole pattern difference in Eds photo that would be about right. A quick tape measurment should read 3-15/16 on the adapters if dial calipers arent available.First let me say that I doubt that I would have this TD were it not for all the great help and support that this forum provides.
Assuming that I can not find blank front drums (and it does not look promising). And realizing that I want the same “rig” on the rears as the fronts.Here are my options (I think):
1. Weld “ears” on the adapter and drill holes for 4×130 in the ears.
Allows easy switch back to steel wheels.
May have an interference problem with the inside of the wire wheel “basket” hittingthe wheel lug bolts that hold the adapter on.
2. Weld a circumferential washer like hub around the outside of the adapter.
Allows easy switch back to steel wheels.
For some reason this sounds easier to me than ears.
Would allow welding the “washer” all the way around the adapter.
Same possible problem with wheel interference as above.
3. Weld shut the old 4×130 holes and drill and tap the brake drums to the adapter pattern.
Can not put old steel wheels back on without having 4 spare brake drums.
Can the brake drums handle the heat of welding??
Should have no interference problems with the wheel basket and lug bolts.
4. Weld the adapter directly to the brake drum.
No lug bolts.
No interference problem.
Reduces the stance. Tires might fit a bit better under the fenders.
Can not put old steel wheels back on without having 4 spare brake drums.
Can the brake drums handle the heat of welding??5. If there is any metal at all between the holes for the 4×130 lug bolts and the new pattern, justdrill and tap the brake drum to the new smaller pattern.Simplest.Allows easy switch back to steel wheels.
No welding.Is there a danger of weakening the drums.Would there be enough meat in the brake drum to adequately grip the lug bolts?6. Rotate the adapter 45 degrees and weld build up the back side of the brake drums.Then drill and tap through the new welds.Allows easy switch back to steel wheels.Same welding concerns as above.Are there any other ways?Comments?? Votes??I see that you guys were having a conversation while I was composing. I have micrometers and calipers and everything that a guy could want except dollars. Paul, those drums do look like a possible solution. Thanks, BUT $436 plus shipping. Whew. This would boost the cost of my el-cheapo job to about $800 plus tires and tubes. I hope to find a more affordable way.
Royal I just read , but not confirmed the triumph stag wheels were on a 4 x 4.5 ” bolt circle. If that is true you may be able to get VW wheels for that pattern someplace like cip1 where Paul found the 4 x 100mm wheels in his post above.
Sorry, I didn’t even look at the price on those drums. Ouch!
Just noticed the footnote that the 4 x 100mm is the Rabbit/Golf bolt pattern.My humble opinion…Options 3 through 6 all bear significant risk, based on the issues of welding the cast irom drums. Others with more technical background than mine have already commented on this.One comment on item 5 specifically, when you look at the back of your drum, you will see the cast metal is thicker where the VW stud holes are. The metal is thinner between the holes.Option 2 seems to be the soundest in terms of safety, providing a full weld around the circumference of the adaptor.Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
Roy, It’s been a while since I have seen the inside of a VW brake drum, but I think I remember 4 spider web like areas where the bolt holes are located. If you drilled the drums to match the adapters in between the existing holes and use studs with washers on them , would the washer help to distribute the stress over a larger portion of the drum? The use of studs sounds stronger since they would not depend on the threads in the thinner part of the drum. Just thinking on this ,get more opinions before you do this ,it may be unsafe!!!
Mike, I didn’t know the thumb rule of the diameter of the bolt being the same as the thickness of the plate. Sounds like overkill on anything over 1/4″ to me. But, I’m still learning.
Larry, If I could safely do something like you describe, it would certainly be the cheapest and quickest. You are correct in remembering that there is a spider like raised and reinforced ribbing where the drums are tapped for the wheel lug bolts.Paul, Option #2 would be as safe as could be. I am keeping this one on top of my list pending a very close check for interference. I may try to get my brother (an expert at everything mechanical) to weld up my adapters like this if no interference.Thanks guys, I’m still listening.I find it hard to believe that no one else has done this before and that I am blazing a new trail. I really expected to hear some lessons learned the “hard way” from some of you.We’re changing your name to “ground-breaker” Roy!
Didn’t think you would graduate from apprentice to master so quickly, did you?
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
Just to note: welding the spline hubs on would be the perfect solution if you never plan to do a brake job or grease your bearings again. You would lose access to the nut that holds the drums on . . . .
Royal if I had one of my old drums I would drill and tap it at work . I could see what the drum thickness was and at the same time do some improvised stress test (aka whacking a screwed in stud with a big hammer). Cast iron is brittle by its nature and cant handle shock well, but has great wear resistance in a scrubbing motion. It takes extreme heat and thermal expansion well if allowed slow cool down, but can crack if hot and rapidly cooled. If i recall VW drums have no boss for the wheel to ride on and all the shock goes to the lug bolts. The 14mmx 1.5 lug bolts translate roughly to 9/16 diameter x 16 thread per inch. If you had as much as 3/8 thickness in the drum you would still only have 6 threads engaged in the drum. Small amounts of thread engagement is what causes threads to pull in soft metal or chip out in hard or brittle metal when under stress. If $ or clearance was not an issue, I would suggest having a machine shop weld 1/4″ plate about 6″ diameter to the back of the adapters, turning and facing the plate true to the splines. You would also have to clear out the center of the welded on plate by boring while in the lathe. They would then put the adapter in a mill to drill the bolt circle. Once that was done they would need to spot face the bolt holes on the splined side to clear out the new hole area where the original back laps about half the new hole. The down side on this is I estimate about $100.00 per wheel. The upside is it would be extremely strong and running true and in balance as all machining would be concentric and parallel to the original splines plus you would not have to remove or alter the drums. Sorry for the long winded post about machining, but this is one project that would be hard for the home mechanic to do.
Mike, thanks for the recipe to getting this off the ground. It’s sounding more and more like a project for my brother John who wouldn’t be intimidated by all of this, but I was hoping to do it myself. You say “Once that was done they would need to spot face the bolt holes on the splined side to clear out the new hole area where the original back laps about half the new hole.” I don’t understand this. ??? I understood and agree with all the rest.
Ed, I guess that you are saying that the nut would be recessed too far to get it off? I was able to get it off on my TF. I wish I could remember it more clearly – too long ago.Royal, spot facing is a machining term that for example when a hole is drilled into a rough cast or uneven material a counterbore tool or endmill larger than the bolt head diameter for the drilled hole is machined to smooth down the surface where the bolt head makes contact. Another example, but more extreme is when the counterbore goes deeper to make the top of the bolt head flush or below the material surface. The adapters would need to be spotfaced like this because some of the new bolt hole would be partial in both the new and old back plate on the adapter. If you look at the photo in Eds mock up you can see where the back plate covers part of the drum holes. You would only be spotfacing that area in the old plate down to the new welded on plate so your lug nuts would clear. Like I said in an earlier post I am in no way trying to discourage you from this project because I think you are a man that has tackled much more than this. I only want to offer you and other members here any help I can in an area I have a little knowledge. I value everything I have learned here and am thankful for the diverse background in mechanics and electronics that members have contributed to help each other. Again I am watching this project of yours with a lot of interest and do believe you are about to do what a lot have thought about, but were hesitant to start.
Thanks Mike, Now I understand, I wasn’t familiar with the term. Your “recipe” is actually a refinement of my Option #2 (I think). Yes?? Seems that the best direction to go hinges on the lug bolt to wire basket clearance question.
Roy, yes it is basically the same as version #2. I just feel for other than for mock up you will need to get a machine shop to to turn and face the new plate concentric and perpendicular to the splines. Also with no boss for the adapter to seat on, the lug bolts are what makes the adapter run true and in balance. That is why I think The bolt pattern needs to be put in with the precision of a mill. I think the adapter modification is the best route to go here unless you find the drum has sufficient thickness for drill and tap. I would not be surprised if at some of the VW sites you will find guys that have just drilled and tapped the drum without taking into consideration of the material thickness. I have have done things like that myself at 22 or 23 years old, but would not do now because of what we learn in age and bad experience. Please dont think I am trying to take control of your project as there could be other alternatives to what I suggested. I am just trying to help .
Mike N Scarlett2012-05-02 09:06:47
Mike – Nicely done! You added much necessary detail to what we all intuitively thought was the best approach.
And um, kudos to Ed for pointing out the obvious flaw in welding the adaptor to the drum. That was a major “duh” for all of us!Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
Roy: you lose access to the cotter pins that hold the castle nut in place. They’re tightened just so, to leave a bit of play for the bearing. Without the pin, I think they’ll loosen up, or maybe tighten up. Either way, bad, and no way to get the cotter pin in or out through the hole in the middle of the spline.
That said, the 4 x 100 ready-made bolt pattern drums might work. You could drill four new holes in the adapters in that pattern. Still have to figure out if the actual wheels would like that though.
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