The hydramount,a new theory.....discuss
 

I have a new theory about the Hydramount. I have two brand new diesel
Hydramounts and the old original which was passing serious vibration back to
the steering wheel and the seats. When fitting the new mount cured the problem I assumed that the old one had softened with use and was allowing too much
engine movement coupled with the fact that the rubber had many splits in it.
This does no tally with the fact that the two new mounts are easier to bend
back and forth than the old replaced one! In other words the rubber is more supple. I have come to the conclusion that the reason we have to change the Hydramount is because the rubber has stiffened with age which means that it cannot allow the normal amount of engine movement without passing
some of it back through its lower mounting on the chassis to the steering wheel and seats. I was able to compare the engine vibration at tickover on my car with my sons diesel which needs a new mount and they feel identical but my car has no wheel or seat vibration now whereas his is quite bad. In other words the new softer mount is better able to isolate the same amount of vibration from the chassis.

Interesting theory, which seems to make sense to me. I am thinking of changing the hydramount on my CDTi (I have already changed the lower engine and gearbox mounts) to remove some residual vibrations at certain engine speeds that result in a dashboard vibration and an irritating buzz from the door locking button on the drivers door (right next to my lughole !). I am also suspicious of the poorer refinement on my present car from it running on lower profile tyres on alloys, compared to 15 inch steel wheels with higher profile rubber on my earlier 75, which was much more refined. In fact, yesterday, I ordered a set of 15 inch steel rims from a scrapyard that are breaking a basic spec 75 classic - 4 rims for 60 quid - I plan to put Goodyear Vector 4 seasons tyres on them (60 pound each for the 195/65 R15s from mytyres) - I expect a quieter, smoother ride on these, but I'll keep folks on here updated.

BTW - is the hydramount change difficult ? - a basic 'how to' post would be helpful, although I can probably work it out for myself once I get the spanners out !

Thanks

Pete

Does sound plausible. Considering age of these mounts - most 10+ years. Think of a tyre at that age.

Looked at mine whilst doing thermostat. The rubber is quite crazed and almost cracking. No bad signs of vibration in car though (only annoying little vibration at 1800rpm ish).

And the same as EastPete - dashboard buzz (seems to be come from sunlight sensor area) and both central locking buttons vibrating - but also seem to be dependent upon coarseness of road - have a ZT so 18 inch wheels and budget tyres,

Do you have a picture of the condition of your Hydramount wuzerk? Thanks. Would be good for comparison purposes.

Probably the same reason many prefer the rubber bushed lower tie bars to the new PU versions.

TC

you can solve that door locking buzz by putting some mcdonalds straws over your door locks, cut them down the middle and in half and slide them over. problem solved!

Hydramount
 

Here the pic of my diesel Hydramount which was allowing serious vibrations
to reach the steering wheel and seats

Note the splits in the rubber which I now believe are because it has hardened over time losing its ability to absorb the engine vibration without passing it through the car.
http://imageshack.com/a/img829/9616/px5v.jpg

The 15" wheels, steel or alloy, will obviously give a softer, quieter ride with a decrease in cornering ability.
The Hydramount is easy to change unless the mount itself proves difficult to unscrew from its mounting. It has a metal band around it with cutouts in
it which a special tool fits to unscrew it. You can use a drift on these flats. If it proves difficult then, on the diesels, it is easy to pour some releasing fluid into the bottom cup in which the Hydramount sits and leave to soak in. Mine released after five minutes. The petrol models do not have the bottom cup fitted. You must drop the engine undertray, remove one of the 15mm bolts from the lower engine mount and loosen the other one so that the lower mount can hang free and not cause the engine to be
prevented from being swung, at the top, into the correct position to undo the rather large casting which sits on top of the Hydramount. To remove this casting you need to jack up the engine slightly,remove the engine cover, the power steering reservoir bracket (easy), the nut on top of the Hydramount, and four long 15mm bolts holding the casting to the engine.
Then, with the two 15mm bolts connecting the top link to the secondary engine mount (bolted to the O/S inner wing by three 15mm bolts) removed the whole casting complete with the linkage will lift off.
I will try to add some pics next.
This pic shows the two 15mm bolts which need to be removed on the link (the two with a black line across them). Apart from removing the top nut from the Hydramount, and the upright bracket holding the power steering pipe that is all in this area. In the bottom R/H corner of the pic you can see one of the long 15mm bolts holding the top casting to the engine. More pics to follow.
http://imageshack.com/a/img537/7122/4473ab.jpg

Hydramount
 

Thanks wuzerk for the image.

Yours looks like a 8/9 (out of 10) for damage - mine is more like the lighter crazing below the top ridge of the hydramount. So I would estimate more a 2/3 at the moment.

Will keep an eye on it.

Hydramount change cdti
 

After changing my lower engine mount to a mondeo mount, the vibration through the body is still there when accelerating, my next move will be to change the Hydramount, i cannot see any cracks/perishing of the rubber body, after reading many posts on this subject,looks like this could be the culprit.