Rear Engine Stabiliser Mount.

[cass3958]

Driving out the other day in my 1968 S Type 3.4 auto and noticed under load and especially up hills I was getting a knocking noise as if a rotating item was hitting a static item. On the flat and having lifted off the noise went away.

Today I got the car up on the ramp to check out the noise and could not find anything touching but then the engine was not under load. Nothing was loose but I suspected propshaft U/Js so decided to whip the propshaft out.

As I supported the gearbox prior to removing the gearbox mount I noticed a lot of downward sloppy movement when I pulled on the tail of the gearbox. The downward movement was allowing the propshaft to hit the top side of the gearbox mount. Removed the gearbox mount and spring and immediately found some rubbing marks on the gearbox mount and the edge of the rotating propshaft so there was my noise.

IMG_9950.JPG (3.84 MiB) Viewed 1996 times

IMG_9952.JPG (2.52 MiB) Viewed 1996 times

IMG_9951.JPG (4.92 MiB) Viewed 1996 times

With the propshaft out I checked the U/Js and as far as I could tell they were fine but I will replace them anyway as it was not a job I did eight years ago when I rebuilt the car.

With the amount of travel I have in the tail of the gearbox I am now assuming that the rear engine stabiliser has gone and have ordered along with the U/Js a new rubber bush for the stabiliser. I remember when I put the engine in the car how difficult it was to get to this stabiliser which for those who do not know is down the back of the engine. It connects the top of the bell housing to the bulkhead and stops the excessive up and down movement I have got.

I am going to have to remove the bonnet and possibly even build a platform over the engine that I can kneel on so I can get to the bolts holding it in place. I think I am also going to have to remove the water pipes from the inlet manifold to the heater box. Has anyone else changed this stabiliser and can suggest any tips on how to get at it and change it please.

[JCS]

Rob
As you will see the bonnet needs to be removed and I seem to remember you may find it advantageous to remove the battery.

On my own car I removed the steel heater pipes a long time ago and fitted (16 mm?) rubber heater hose. Removing the steel pipes, if that is necessary, might become the most awkward job, I believe they are supported under the inlet manifold. If you want reliability, I would take the opportunity to eliminate that potential cooling system rust provider. Don’t have visions of using stainless steel, it is not easy to form, or for that matter to remove and refit. You might need to prepare yourself for needing to replace those heater pipes if they have rusted badly internally. The shape of the original pipes makes them all but impossible to remove with the carburetters in place……..so that might mould your decision on whether to try to salvage the pipes or replace them with heater hose.

Looking at your images I think you will need to replace the main rear mounting spring and the rear seating bushes. I would be interested in knowing the length of that spring of yours. There were some considerable spring changes over the production life, do you think you have the correct spring?

You might consider replacing the cam shaft oil feed pipes, or at least have some of the very special sealing washers on hand. Again, I replaced the rigid oil pipes with flexible hydraulic pipes a much better arrangement than the rigid brittle oil pipes. My car has the different oil pipes but I don’t think you need to disturb the originals.

It is worthwhile building a bridge across the engine and I have suggested that in another thread. When I was working, all our workshops had these in use on a daily basis for working on a variety of equipment.

I strongly suggest you do NOT slacken or remove the four set screws retaining the two brackets to the bell housing, but remove the large cross bolt instead.
Make up a piece of bar to match the diameter of the cross bolt and taper the end, use this to align the final assembly so the cross bolt slides into place. However just before lining up with your alignment bar pinch the two brackets slightly so that they grip the lower bush, this will hold your stabiliser while you use the alignment bar and fit the cross bolt. Work out a method of holding the cross bolt head and nut because I remember it being difficult to get two hands around that area.


Norman

[cass3958]

Thanks Norman.

Most of what you have said I have already made a note of other than the locating dowel for the cross bolt. I know it is going to be tight down the back but I did it when I put the engine in so I should be able to do it again but it is strange that it is only eight years ago but I have already forgotten how I did it.

I have ordered a new spring for the mount with new rubbers. The old spring is 4 inch but the new one which is original spec from SNG has not arrived yet so cannot compare them.

Before I starting getting this noise, if I went over a speed bump or a pot hole too quickly, I thought the suspension was bottoming out hitting the bump stops but now I think that it has been the tail of the gearbox hitting the mount. The spring in the mount seems very soft and I have no reason to believe it is not the original so maybe a new spring with the rear stabiliser changed and that noise will go away. All the parts only cost £30 so no reason not to change it all.

You can buy stainless steel heater pipes but they cost just over £100 and mine were fine when I fitted them so no reason why they should not still be OK. Running rubber hoses does make sense other than they are not contoured to fit behind the engine and they would not be original.

Just have to figure out how to set up a platform over the engine that I can kneel on.

[Glyn Ruck]

Barratts sent me the uncompressed length of each spring & number of coils by e mail but I can't find it. I fitted rubber cups on both ends of my spring & the vertical shaft bush. The parts manual only shows 1 cup ~ error? (Plate 1 - Item 90). I have the same newer rear engine/GB mount (89) as you on my MOD which is correct for later cars. My old spring had softened considerably. Auto & MOD springs are quite different in length.

Rear engine mount1.JPG (34.36 KiB) Viewed 1974 times

Rear Engine Mount.JPG (43.27 KiB) Viewed 1974 times

IMG_3537.jpg (193.6 KiB) Viewed 1954 times

I think the single spring cup was intended for the early car rear mount.

Old Rear engine mount.JPG (83.13 KiB) Viewed 1974 times

I agree with Norman on the rear stabaliser cross bolt to change the stabaliser bush. Leave the 4 bracket bolts alone.

I fitted the stainless heater pipes but they were cheaper when I ordered. My steel pipes had rusted through & on their way out.

[RollyTG]

Rob - I recently looked at replacing the rear engine stabiliser also. After removing the battery and and battery tray and disconnecting the heater hoses I basically came to the conclusion that there is absolutely way to get at and undo the lower bush bolt and gave up on it. I think there must be some special tool required. Hopefully there is a trick that I couldn't come up with.

[cass3958]

Today I changed the rear engine stabiliser mount. Not as hard a job as I thought it was going to be. Once the bonnet was removed with the air filter and the battery access was quiet good. No need to remove the heater pipes as these could just be set to one side still attached.

I was only intending to change the rubber bush at the top as the lower joint with the cross piece as far as I remember is a solid joint with a brass of metal sleeve and should not have any wear.

First thing to do was to check I had supported the gearbox correctly as I had removed the gearbox mount from under the car whilst doing the propshaft. The rear stabiliser has a single 9/16 nut in the centre which holds the centre spindle to the top of the bell housing.

Showing the 9/16 nut removed.

IMG_9967.JPG (914.2 KiB) Viewed 1907 times

This was released and removed. Next there are two ½ nuts and bolts either side of the rubber mount which are difficult to get to. The top is easy enough to get a socket on to but getting an open ended spanner on to the nuts underneath was tricky. I had to employ my lad to help as he has smaller hands than me. On the heater side it was not such a problem and I set up the spanner with a strong magnet attached to it so as we released the nut it stayed attached to the spanner until it was withdrawn. On the battery side it was a lot tighter and we tried the same technique but as we tried to withdraw the nut there was no room for the magnet to remain on contact with the spanner and the nut fell down on top of the bell housing. If it had fallen all the way to the floor it would not have been a problem but it got lodged on to of the bell housing and took an age fishing with the magnet until we eventually caught it and it was retrieved.

The rubber mount was then removed and came out in two parts as can be seen in the photo. Old on the left new on the right.

Old on the left new on the right.

IMG_9969.JPG (1.3 MiB) Viewed 1907 times

Old on the left new on the right.

IMG_9968.JPG (866.8 KiB) Viewed 1907 times

The bond between the metal sleeve and the rubber mount had sheared allowing the gearbox to jump up and down. Taking hold of the threaded bolt I was able to pull this up and push it down to feel if there was any play in the lower joint but I could not feel any. From this I decided not to even try and remove the lower section as I could clearly see that the damage was to the upper rubber bush.

The old mount was easily replaced with the new one and was a lot quicker to fit than it took to remove the old one. Everything was reattached with the help of my son.

I know the roads around Torbay are bumpy and we often comment on their destructive power so I am not sure if it is the roads giving the bushes a real hammering or whether the standard of rubber bush has deteriorated but in the eight years since I rebuilt my S Type with all new rubber bushes I have had to change the radius arm bushes twice and will have to do them again in the next couple of weeks, I have changed my engine mounts after one sheared off allowing the fan to go through the radiator. I have changed the front anti roll bar bushes and the exhaust rubber mounts throughout the whole system. I appreciate that I use the car on a regular basis as a wedding car, to go to the golf club or the supermarket but they are all fairly short journeys and I have only done about three thousand miles in the last seven years. The longest journey being to Coventry and back around 500 miles so why are my rubber mounts deteriorating so quickly? Still it gives me something to do during the week.

[David Reilly]

see attached.
Cheers
david

[cass3958]

Thanks David very interesting but I don't have the front stabilisers on my car being a 1968 and no A/C unless you include the quarter light windows.
I will look up the correct procedure for adjusting the rear stabiliser though as I have a Mk2 manual lying around somewhere. I have not looked but from the comment in this letter I take it that it is not included in the S Type manual.

[Glyn Ruck]

It's in the S type manual. I have not given you the front stabalisers as you don't have.

Rear engine stabaliser.JPG (99.94 KiB) Viewed 1895 times

[cass3958]

Thanks Glyn I had not looked in the manual myself. This was how I did it years ago so I have not adjusted the lower flanged washer "D" just left it as it was. I cannot check the adjustment yet anyway as I have removed the gearbox mount to do the propshaft U/Js and the gearbox is supported by a cross bar and chocks. Once the gearbox mount is back in place I will check it is set correctly which is fairly easy to do as you only have to undo the 9/16 nut and remove the top washer to get a screw driver down to the flange washer.