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What method to repair front subframe left motor mount crack?


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I don't own a welder but would like to do as much as possible my self.

A. Can I drop the subframe while somehow supporting the motor with a board across the fenders? If I do this can I leave the struts and brakes in?

B. If I had a welder come to my house (like my brother) would it be easier to pull the engine and weld the motor mount back on while leaving the subframe in the car?

My guess is A.

Also, any repair pics?

TIA

Ray,  Current BMWs, 1973 BMW 2002, Turkis, and 1997 BMW 318i 5sp avus blue.  Drove a lot and sold over the years, in reverse chron.

     1997 m3 coupe silver, 1998 318ti red, 1996 318ti red,

     1973 2002 Agave, 1971 2002  GM brown

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I dropped the subframe with the steering box still bolted on. (Pitman arm and idler arms came off.)

I had to remove the control arms and the strut bar that connects the subframe to the control arms. The sway bars came off too.

I had access to a sling. It sat on the inner fender, and had a chain to hoist the engine up off the subframe. Very cool.

I also replaced the oil pan gasket while I was at it.

I actually got a replacement subframe instead of welding mine. I had a spare from a car I parted. I welded a piece of steel to reinforce the motor mount bracket, attached the steering box, and reassembled.

I should have taken pictures of the subframe prior to the install. My bad.

Good luck.

Pierre

O==00==O

69 2002 (M20), 74 tii, 76 533i, 79 323i, 80 732i, 84 323i (S50) 91 318is, 96 318ti (S52), 97 Z3, 02 330i, 03 525iT, 02 R1150 RTP.
Auxiliary Lamp Brackets  Kamei Reproduction Front Air Dam

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I did it in place. Remove the alternator, move the battery to the trunk and get rid of the battery tray. Thoroughly shield the steering box. Generally clear the area. Put the car on jack stands, high enough to get around under it, in a hood with leathers on (cover your ears so you don't catch a hot one). You will work from the top and bottom on this. While underneath you will work from the front of the as well as the rear of the subframe. The rear is very difficult. You will be happiest if you also remove the intake manifold. Once you have gone this far you may want to consider doing a 5 sp conversion and a motor rebuild.

When you are done it will in all likelyhood look like hell and you will be pissed off because you cannot make it look better (like Tkent's). You can then start looking for a replacement front subframe to redo and reinforce while you do the big brake conversion. Several thousand dollars later you will hang the original subframe on the wall to remind you of the assorted things you learned through the process...and you will feel good!

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There was a post a while back that was excellent on this topic. One thing I remember was that someone mentioned that prior to welding you MUST drill out a hole just below, at the end of the cracked area. This will stop the crack from going any farther. Even if you weld what will happen if you don't drill out the crack is it will come back. Maybe someone who knows what I'm talking about can elaborate more??? Just make sure you take a 1/4" or so sized drill bit and drill a hole so the crack stops growing.

HTH & good luck!

TJW

'79 & '80 Vespas, R75/6 + R90/6 (and a Triumph), '76 IH Scout II

E36 

'71 VIN: 2574356 - Nevada, Sunroof, RUST and a really nice '76

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Undid the bad mount. put a bottle jack between the block and the fender to push it away from the mount a little. cut a piece of 1/4 (or 3/8ths, can't remember) in steel that fits inside the cup of the mount. welded up the mount and ground the inside smooth. then wedled the reinforcement plate to the inside of the mount. drop the bottle jack and bolt back up. I have been running like this for three years, with a lot of hard driving without any problems.

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