Broken Clutch Slave Cylinder engine mount
 

2005 Cooper S.

Royal f-up while replacing the clutch slave cylinder.

One of the mounting bolts broke while removing the old slave cylinder (see pic with broken bolt and red arrow). I drilled out out most of the bolt and then hit the remaining bolt threads with a hammer and hole punch but unfortunately snapped off the slave cylinder mount while doing this (see pics of broken-off mount and also the engine block with red rectangle)

Would greatly appreciate any suggestions.

My thoughts are to JB-weld the mount back to the engine block as a temporary fix and then take it to get welded permanently. One question is whether the JB weld is heat-tolerant enough to be applied directly to the block (it says tolerant to 550 F). Another is whether the slave cylinder applies too much force compressing the clutch for a JB-welded mount. A final question involves welding to the engine block; I have no experience with this and just don't know what to expect.

Many thanks in advance.

Temperature isn't the problem, I'm hesitant to believe that JB weld will hold. Welding it would likely be the better option, but finding a capable welder is difficult because it's a cast aluminum (I think?). I'd call around a few metal shops in your area and see what they can do for you.

Replacing the housing half would likely be the best option, but it would be the most labor intensive (having done the transmission myself). My spare transmission has a weld on it, but it's more for sealing than for structure. If you drive to Illinois I'd sell you the whole thing for $200.

Oh one last thing, that's actually the transmission the mount is on; not the engine ;)

https://cimg5.ibsrv.net/gimg/www.nor...cf01131cc4.jpg

thanks for the info. Illinois is so far from here...

indeed, i have concerns about welding it as it does indeed look like aluminum.

and i agree that jb weld is insufficient strength.

i am thinking about using a steel plate to support the mount. this would involve drilling and tapping both the transmission body (thanks, not engine) and the broken mount and then attaching the steel plate to these threaded holes, thus supporting the mount against the transmission. this would be in addition to a generous foundation of jb weld.

any other ideas?

Your last suggestion is really the only option besides welding it. I did the same thing, and came up with the same solution, the only reason I didn't try it was that my transmission was out and fairly easy to just take to someone.
And yes it is aluminum and harder to find someone to do the job mobil. (Coming to you).

Wholie crud! That's the solution we're looking for!

thanks for the helpful info.

how did the weld hold up for those who have welded this?

i've talked to a few welders who are hesitant about welding cast aluminum.

thanks for the link to the FTT gearbox bracket. has anyone done this on the transmission that is still in the car? drilling the hole in the supporting bracket (see red circle in pic) and also filing down the surrounding area looks tricky.

The bracket does look like a very viable solution.

As far as welds holding up, I don't think it's really much of an issue, esp. in a stock or near stock application, since 50% or more of the structural support for the cylinder is still being handled by the transmission case itself. The real test would be in a racing clutch and pressure plate application and the increased forced needed for operation, this is probably why the bracket mfg's mention it specifically.
As far as doing the job, just put the car in service mode and take most of the PITA variables out of the picture.

What did you end up doing to fix this problem? I'm facing the same problem, and don't know if the shop will weld it back.

Hey man, I ended up making my own bracket out of thick steel and attaching it to the transmission with bolts. I'll upload some pics.
However this was a major PITA, and I would strongly recommend buying and installing this bracket:
https://orranje.co.uk/product/ftt-ge...ation-one-only
i think both the money and time would be well worth it. If I could go back, I would have used this method (although mine has worked out just fine!)
You will have a hard time finding anyone to weld it directly to the transmission. Also, because this is aluminum, evidently welding it is problematic.
Good luck.

here it is. if i remember correctly, i didn't want to wait for the package to ship from the UK. but believe me, not worth the time making it yourself.

Ahh I see. Yea I already pulled off my transmission and I'm going to bring it to a shop tomorrow. If worse comes to worse I'll just order the bracket.

sounds pretty hard-core. did you get it welded? you got any pice?

The shop wasn't able to weld it because all they had was a mig weld. I put in an order for the bracket but the site has to calculate shipping before it will go through. I don't know how long that will take, so my clutch swap will be delayed.

Same thing happened to me I thought I was SOL as well. I just googled "welding" in my town and called the first guy that came up, called, asked if he could weld cast aluminum, yep, took it to his shop paid him $45 and I was back to work in less than an hour. Moral is that if this happens call around, you may get lucky, like me, if not you always got this bracket thing to fall back on.

Hey man thanks for posting. Your experience is significant because i couldn't find a welder who was willing to work on mine - I probably called 10 shops. Did you remove the tranny or tow the car in? Do you know what type of weld he used?

If mine breaks again would be great to explain how you did it with another welder to demonstrate that it can be done.

I am sorry, I do not know the type of weld he used but all I took him was the broken gear box. Anything can be welded, it is just finding someone that knows how(like great BBQ ;-))I did not have to disassemble the trans(whew) as it did not get that hot and I had drained the gear oil(naturally) Seriously all I did was call the guy and ask, "Can you weld cast aluminum?" When he said yes, I asked if he was available, the rest as they say...He did also remove the broken stud but I didn't watch him do it as he took it in to his shop.(I would have drilled it out)
FYI in the future, get on Youtube and search for a product called alumaloy. This is what I was going to do but I thought I would give the welding a shot because I did not want to wait.(order. ship, etc) Had I not found a welder, that is what I would have tried, because replacing the gearbox...no...I did not know this bracket was an option at the time. That product looks like it would have worked as well(done correctly) but I have zero experience with it so I can not vouch for it. It would be interesting to play with though before I had to actually "use" it.