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For the 2nd time we are having issues with the dogbone/gearbox mount on our G.

It is a rubbish design, the hole inside the large end which fits into the subframe is larger than the bolt which goes through it and the mount relies on the clamping force of that bolt to stop the mount moving around.

For the 2nd time now we are getting problems with the bolt either stretching or the subframe distorting which has resulted on the mount moving around and the exhaust or something hitting the subframe whilst pulling away or changing gear.


I am thinking of machining up a bush to take up the slack between the bolt and the hole in the subframe.

I don't suppose anyone has the size of the hole at the large end and the size of the bolt? I think the bolt is M14 but I am not 100% sure...

Many thanks. :)
Here you go Symon, I fitted my powerflex bush today so took some measurements for you. Hope they help if its not too late.

If I were you though I'd just fit one of these bushes as you get a spacer bush that takes up the slack made form the same PU as the actual bush. The difference it has made is surprisingly noticeable and has totally transformed the gear changes on my TCT. I went in with low expectations and thought I'd give it a try seeing its such a cheap and easy job. The gear changes are now super smooth and has lost the slight jerk that you could feel from the engine twisting as it changed gear. I really didnt expect to feel such a marked improvement.

Also it hasnt added any vibration to the car as the powerflex website warned against. I even fitted the harder black series mount intended for track cars.

I highly recommend fitting one to anyone considering doing it.
 

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Discussion Starter #23
Excellent. I have decided to leave things as they are for the time being, but if it needs attention again I will certainly be doing this mod.
 

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I had the standard yellow one fitted on my manual 1.4 MA.
Noticeable difference indeed. No more clunking when shifting,
and during load shifts.
From your measurements the duameter difference between bolt and hole is 10mm.
Granted I didn't measure, but the PU cylinder wasn't 5mm thick.
Yet the mechanic confirmed that the fit was snug.

Definitely recommended.
 

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I had the standard yellow one fitted on my manual 1.4 MA.
Noticeable difference indeed. No more clunking when shifting,
and during load shifts.
From your measurements the duameter difference between bolt and hole is 10mm.
Granted I didn't measure, but the PU cylinder wasn't 5mm thick.
Yet the mechanic confirmed that the fit was snug.

Definitely recommended.
I wasnt sure if I should fit a yellow or black one so bought both to see how much difference there was in the hardness. There was very little actually and I figured the movement in the unmodified one was down to the holes and not the rubber itself so I went with the black one as its more discreet. I think filling the holes was what made the difference rather than the hardness of what material it was filled with. As a result I have a spare yellow one now so will measure the PU cylinder tomorrow to find out the size of that. As symon was thinking of machining one from stainless I thought it best to take accurate measurement from the original bushes themselves. The holes in the original bush is only a rough casting anyway so not exactly precise.
 

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Giulietta 2.0 170 Veloce, 2013
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How easy is it to get the mount out and off the car? It looked very tight when I was under doing a service. I may order the powerflex kit and do next weekend along with suspension.
 

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Im lucky becuase I have access to a lift so can get under the car with plenty of room. I dont think Id like to do it lying under the car in the road. However there is plenty of room around the mount and none of the bolts are hard to get to. You'll need a 21mm spanner or long reach socket plus a couple of large torx sockets ( sorry not sure what size they are ) Heres a couple of pictures of them.

to pull the mount out of its hole I took out 2 of the bolts holding the mounting bracket to the engine ( there are 3 , No.9 in this diagram) and left one in, That allowed me to swing it away to give more room.

They are tight so I used a bit of scaffold tube on the end of the socket wrench for more leverage.

The whole job was fine to do honestly, just have the right sized sockets to hand and a length of tube or long bar and youll be fine.
 

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Thanks, I'll order the bushes today. Looks fine after seeing your pictures. Was a pain on my last car as various other bits including exhaust needed moving.
 

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I recommend a second pair of hands for when you have to put the bolts back in.

I found my engine rotated (forward?) Without the mount in. So someone to help twist it back into place whilst you get the last bolt through is very helpful.

Otherwise it's a nice easy job with some annoying to access bolts on the mount as the exhaust gets in the way when getting the sockets on.


Makes a very very nice difference to the drive though.
Good luck.
 

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Discussion Starter #30
It's an easy job as long as you undo the gearbox end first. Ramps or axle stands are a must though unless you are lucky enough to have a pit.
 

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Hi
Did you use a torque wrench or just did it up tight?also I thought that there were only two bolts you have to undo...why the third?
 

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Discussion Starter #32
I just did mine up tight. It might be worth putting some threadlock on the 3 bolts which go from the bracket to the gearbox if you undo them.
 

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Hi
Did you use a torque wrench or just did it up tight?also I thought that there were only two bolts you have to undo...why the third?
I used a torque wrench but you can get away without one. As symon said , very tight is good enough. Not sure Id use thread lock on any of them though, The ones I took out didnt have any on them from the factory and they are so tight theres little chance of them coming undone, plus the thread lock will act like a bit of lubricant and you run the risk of over tightening.

The reason I took out two of the bolts on the bracket that bolts to the engine/gearbox was that the bracket got in the way when trying to pull the engine mount out of its hole in the chassis. by taking two of the bolts out and leaving the third one in you can swing it out of the way giving you clearance. The exhaust didnt get in the way of mine but that might be just a different engine to bbadger, I have a 1750 veloce.

Replacing the engine mount i did in this order - bolt No.8 (mount to chassis) then the two No.9 bolts (bracket to engine/geabox) then No.7 mount to bracket. got them all in finger tight before tightening up. As bbadger said when putting No.7 in you have to move the engine a bit but that easy enough by using a bit of wood between the engine and chassis cross member and lever it until the bolt slips through. You only have to move it about 10mm and can easily be done with one hand.
 

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Discussion Starter #35
The ones holding the bracket to the gearbox can come undone.

Guess how I know?

Lol
 

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Discussion Starter #37
It was causing a clonking noise when the accelerator was pressed. Pretty much in the same way as when the bolt through the dog bone mount comes loose, only worse.

It could well have been that I didn't tighten them up correctly after I replaced the clutch 2 1/2 years previously, but they stayed tight for 2 1/2 years...

They now have high strength loctite on them. I cannot see any reason why I would ever need to remove them again unless I am very unlucky.
 

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In my experience all of the engine/ subframe mounting bolts should be torqued to the correct torque. For obvious reasons, especially as in most cases the sub frame bolts stretch.
 
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