mk2 subframe mountings

[johnboy]

Hi I think i need to replace the subframe mounting bushes that sit under the back seat of my 1977 Triumph 2000. What like a job is it to do? Any tips? I think that's what is causing my vibration as tried everything else.

[johnnydog]

It's not too bad being honest. Initially, I would just check for corrosion or stress fractures in the metal work around the reinforcing plate under the back seat - if all is well, I would clean much dirt / underseal etc off the two bushes mounting bolts , and the nut on the large through bolt as you can, and spray them with rust penetrating fluid overnight.
Last ones I did, I started the two small bolts and the nut on the through bolt whilst the car was still on its wheels (I fortunately have the benefit of a pit). I then jacked up the side you're working on, leaving the wheel still on the ground and chocking the wheel itself to stop the wheel / car from moving, but with the handbrake off. I can't remember if I chocked the front wheels too, but it wouldn't do any harm.
Once the bolts are undone, the bush comes out downwards. When replacing it, make sure the thick washers are correctly positioned relative to the anti-vibration strap (CW has detailed info on his technical section)
I used the original washers, and used the marks in the underseal on the body and the anti vibration straps, and on the paint under the back seat, to ensure exact repositioning of the through bolt and bush relative to the old one removed.
If you lift the rear wheel completely off the ground, and have the handbrake on, there may be a possibility the rear subframe box section could move very slightly, especially with the force of the rear springs as well, which may make refitting of the bolt more difficult, and also affect the rear track slightly.
There is no guarantee that yours have not been replaced or off previously, which may negate the accuracy of any previous positioning, but as mine were the original ones from new, I could see the exact position of the original washers etc from manufacture.
I may have gone OTT with my method, but I didn't want any small change of position of the bush, which may then slightly alter the rear track due to any movement
HTH!

[johnboy]

Thanks Johnnydog, That's brilliant I have ordered new bushes from Chris Witor tonight, the floor is actually fine I am pretty certain the last time I checked .

[Forkie]

May as well fit new SS straps whilst there, i did just that when i replaced my original rubber mounts that were completely shot - looks so much better. As John said, follow the witness marks in the original set up from the washers, helps to relocate to the original positions.

[Forkie]

Another thing - make note of how it all comes apart - there are quite a few washers- sizes, above floor/ under floor, vibration strap position etc to ensure correct sequence of rebuild - and dont forget sealant either side of floor pan....

[johnnydog]

I actually had a new pair of stainless anti-vibration straps that I intended fitting. When I offered them up to the car, the angle of each end of the strap didn't sit 'square' to the bush or the floor. I had a pair of brand new 'old stock' steel BL straps and they fitted perfectly.
And I agree with Forkie - although the info on CW tech site is informative, there are other variations in the thickness of the washers that are not detailed, along with variations of the positioning of the thick and thinner washers. I am lucky - my cars are all original, and haven't seen 'messed' with, so the washer orientation is as they left the factory, so I was happy replacing them as removed.

[Forkie]

Regarding those SS straps - having only that option, i did realise after a bit of head scratching that they are handed ( i think on memory they are marked - L and R ) but, they also have to be a certain way up ( not marked) to fit properly. It was some period of time before removing my old corroded straps , to fitting the new SS ones - so i was really glad that i took proper note of how the original ones were fitted - i even put each side together again as i removed them, with a piece of strong card indicating the floor - made re - fitting a lot easier. Mine is also original, hence why everything was shot/ needed replacing

[johnnydog]

I saw there was a Left and Right on the SS straps, and I did try them both ways round, but wasn't happy with their fit. Just fortunate I had some nos steel ones 'in stock'!

[johnboy]

Just a quick question - did anyone have any problems with the big bolt coming up through the mounting? Cheers.

[Forkie]

Not at all, it all went back fine....