Rear sub-frame mounts

Hi All,

I'm sure instructions must be hidden somewhere in the vast knowledge banks of our members, but I'm struggling to find them.

Any ideas on where to look for simple instructions on how to replace the front mounts on the rear TF subframe.

So far I've only been able to find comments about cutting off the heads of the 14mm bolts and then reversing the direction of the bolts on re-fitting.

What I've not been able to find is any photo's or 'How to guides' of the actual procedure for replacing the mounts.

Just hoping that this procedure is straightforward and has been documented many times and that I've just not been looking in the right location for the info.

Thanks.

Squashman

I managed to replace them without even lowering the subframe. I removed one mount first by unbolting (or shearing off) the two M8 bolts that hold the bracket, then I ground away the M14 long through bolt that goes through the middle of the bracket. Cutting it once is enough to allow you to remove the bolt and the old corroded bracket.
I then drilled out and helicoiled the two M8 threads to accept the new bracket and put the big M14 bolt in the opposite way around (ie from the rear of the car) and but the nut on inside the brackets hollow section.
Just enough room to get a socket on and tighten up.
The other side was much easier as the two M8 bolts came out without any problem.
Doing it this way you can replace the mounts without dropping the subframe, just make sure you torque up the main 14mm bolts.
Sorry but I do not have any pictures of this, but before you start, make sure you have a set of cobalt drills handy in case you need to drill out the bolts if they snap off, they are hard. Helicoils may also be required. Its pretty self explanatory really, so the above description should be enough for you to do the job. The big 14mm bolts are too long to remove in one piece so it has to be cut. Have a replacement for these also before beginning. Cutting the bolts and refitting the other way around is much easier than dropping the subframe. You may find it easier to grind the nuts off these long bolts also.

Sundance

I did this recently, and discovered that if you have the correct 105mm bolt ( some replacement bolts are longer i think) it will just fit in from the front without disconnecting any other sub-frame mounts, you just have to allow the front corner of the sub-frame to 'drop' about 5 or 10mm which gives enough space to wiggle the bolt and bracket into place, but isn't enough to subject the other mounts to undue stress. I took the opportunity to spray the rear of floor pan / rear bulkhead and mounts with Dinitrol 4941 in the areas MG missed!

Thanks Sundance.

Sounds like I need to allow a long day for this, just in case of sheared bolts (which seems to be the norm with virtually all TF bolts!).

Looking at the state of the round sections on one of the existing mounts its nearly all corroded away so shouldn't have much issue getting the M14 bolt out.

Hi Gavin,

Did you need to cut the old M14 bolt out as Sundance did or will the bolt come out in one piece?

I've replaced both front subframe mounts on the rear subframe and on both sides the bolts sheared and the captive nut broke free while drilling it out. I ended up having to weld in new 'captive' nuts.

https://www.mgexp.com/phorum/read.php?54,3669589,3669589#msg-3669589

i did actually cut the M14 bolt when taking it apart because i had read that this is how it has to be done. But in retrospect i didn't have to, as i could have wiggled it out as i've described above. However, if doing it again, i would be prepared to cut the bolt out, but start by trying to get it out without cutting. The problem is how long the bolt is - they vary i believe. The one i fitted was 105mm, but i believe some suppliers supply replacement bolts which are around 115mm ( which is probably a standard available bolt size) which i suspect is too long to fit the 'correct' way round, hence why many end up fitting them the otherway round. I also had a mounting bolt shear, but managed to progressively drill the remains of the thread out starting with a slocombe drill, and save the thread - but i was lucky

To get the 14mm bolt out without cutting the end off it, you will not have the clearance to withdraw the bolt without it fouling the rear bulkhead of the car. Use a slitting saw to slice the end of the bolt off, while you are at it, may as well just grind the nut off too.
If you contact MGFnTFbitz and tell them what you are up to, they will send you a full set of correct nuts and bolts to do the job, they have stainless mounts in various colours too. Remember its tight to get a socket on the bolthead inside the mount when tightening back up, but its just do-able.
If you spray lots of penetrating oil on the 8mm mount bolts, and use an impact gun, you may stand a better chance of shifting them without pinging the bolt heads off.

Sundance

Thanks for cheering me up Mark!

Really hope it doesn't come to a welding up exercise as that's not my field.
Having said that looking at your MGF photos it looks like your subframe is in a far worst condition than mine.

Anyway we will see how I get on.

Thanks Sundance.

I have already got a full set of St Stl mounts (did the ones on the front subframe last weekend) + fittings etc so, having read the various responses I'll just get prepared with everything I can think of and have a decent flask of Coffee on standby!

The subframe itself is in good condition, only surface rust, but lots of corroded bolts, I've replaced almost all of the subframe mounts bolts.

Sounds like my project.

As I've only recently acquired my TF, the shopping list price for new bolts will soon outway the cost of the car itself!!!