Rear Spring Y Bush an easier replacement

[jtw]

I had the misfortune to have to replace a rear spring Y bush on my 1970 saloon. I read the manual and the procedure seemed fairly straightforward. I jacked up the car, jacked the spring in the middle to keep the tension on the spring, removed all four nuts from the Y bush, now we are ready to prise the bush out using a suitable bar. Well two hours later, after much cursing and various bars and screwdrivers later I could not remove the bush, I was in danger of losing several fingers or an eye during this process. The problem was I couldn't exert enough force on the spring to push it down far enough to get enough clearance to remove the bush. I sat down to gather my thoughts and scour the garage for a possible solution. There it was staring me in the face, it was an old Vauxhall jack, just a single leg thing but small enough to fit in the gap between the top of the spring and the rear chasis leg. You do everything as the manual states, but then instead of trying to prise the bush out or almost kill yourself, you put the foot of the jack on the top of the spring, just behind the clamp which holds the leaves together, then the top of the jack bears on the chasis leg just behind the rear shackle, I hope the photos make this clear. Then you wind the jack up, which forces the rear of the spring down until you have enough clearance to simply lift the bush out, replace with a new one and wind the jack back down, spring goes back up, make sure all the studs go into the slots correctly. Remove the jack, fit the washers and nuts, lower the car back to the ground (with the wheel back on), then tighten all the nuts up. Job done with no risk to life or digit, I reckon using this method you could safely replace a bush in fiftenn minutes.

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[Deleted]

May 6, 2015 20:54:47 GMT jtw said:

I had the misfortune to have to replace a rear spring Y bush on my 1970 saloon. I read the manual and the procedure seemed fairly straightforward. I jacked up the car, jacked the spring in the middle to keep the tension on the spring, removed all four nuts from the Y bush, now we are ready to prise the bush out using a suitable bar. Well two hours later, after much cursing and various bars and screwdrivers later I could not remove the bush, I was in danger of losing several fingers or an eye during this process. The problem was I couldn't exert enough force on the spring to push it down far enough to get enough clearance to remove the bush. I sat down to gather my thoughts and scour the garage for a possible solution. There it was staring me in the face, it was an old Vauxhall jack, just a single leg thing but small enough to fit in the gap between the top of the spring and the rear chasis leg. You do everything as the manual states, but then instead of trying to prise the bush out or almost kill yourself, you put the foot of the jack on the top of the spring, just behind the clamp which holds the leaves together, then the top of the jack bears on the chasis leg just behind the rear shackle, I hope the photos make this clear. Then you wind the jack up, which forces the rear of the spring down until you have enough clearance to simply lift the bush out, replace with a new one and wind the jack back down, spring goes back up, make sure all the studs go into the slots correctly. Remove the jack, fit the washers and nuts, lower the car back to the ground (with the wheel back on), then tighten all the nuts up. Job done with no risk to life or digit, I reckon using this method you could safely replace a bush in fiftenn minutes.

I've already patented that method which I used a couple of weeks ago  I used the car jack to raise the vehicle then inserted the screw jack as shown in this picture which I posted at the time....................................

[enigmas]

A nice straight forward solution there. I have several small bottle jacks very similar to the one you used with a range of about 5" -12".

As and aside, when I was teaching (something practical) often with a group of adolescent boys and I'd see them trying to use brute force to sort a problem...I'd say, "Hey guys, do you know what separates (most of) us from animals"...and they say "what?"...and I'd reply, "our brain."

[Deleted]

May 7, 2015 3:08:13 GMT enigmas said:

A nice straight forward solution there. I have several small bottle jacks very similar to the one you used with a range of about 5" -12".

As and aside, when I was teaching (something practical) often with a group of adolescent boys and I'd see them trying to use brute force to sort a problem...I'd say, "Hey guys, do you know what separates (most of) us from animals"...and they say "what?"...and I'd reply, "our brain."

The combination of the standard car jack and the screw jack gives total and safe control over the removal and replacement and no need to remove the wheel. It can be a quick and simple job which is just as well at the rate the new "contrasonic" bushes wear out

When my Father died in 2007, I inherited a large collection of car jacks, many pre-war and still as good as new. The one in the picture is one of the "newer" ones, a 1 ton jack probably only 60/70 years old but indestructable and I use it a lot  

[Deleted]

I use a similar small bottle jack when changing mine.
When tidying out the sheds I found one of the mounts I started making a few years ago.To my mind these Y mounts need to be comparatively stiff if they are to modify the behaviour of the leaf spring as per the text on 'contrasonic springs. If they are soft they wont. I think the replacements fail because 1 they are fitted to springs that have already settled and are thus under constant shear stress and 2 they are two soft in the first place.
I fitted my mount (which uses stiff Land Rover engine mounts) temporarily to judge the effect on my springs which although old still have some curvature.The ride height was increased by a couple of inches.Bouncing the car up and down by jumping up and down on the bumper(admittedly not a very scientific test) showed no reduction in spring travel.

[jtw]

It all goes to show, you should trawl the P5 forum before attempting any jobs on these cars, otherwise you end up re-inventing the wheel as I did.

[Welsh Warlock]

Jim, it amuses me that you are shown as a Rover newbie!

[jtw]

You know me Alan very understated, newbie I can live with, I've been called a lot worse than that...........sometimes by you.
Call you later

[jtw]

Just an afterthought, JRW still has the bushes to repair the made up mountings which seem to last a lot longer, I fitted mine in 2006, so they have lasted pretty good.

[jtw]

Look at that Alan they've made me up to a rookie already, there's hope for me yet.

[Deleted]

May 7, 2015 9:31:37 GMT @kevbacon said:

I use a similar small bottle jack when changing mine.
When tidying out the sheds I found one of the mounts I started making a few years ago.To my mind these Y mounts need to be comparatively stiff if they are to modify the behaviour of the leaf spring as per the text on 'contrasonic springs. If they are soft they wont. I think the replacements fail because 1 they are fitted to springs that have already settled and are thus under constant shear stress and 2 they are two soft in the first place.
I fitted my mount (which uses stiff Land Rover engine mounts) temporarily to judge the effect on my springs which although old still have some curvature.The ride height was increased by a couple of inches.Bouncing the car up and down by jumping up and down on the bumper(admittedly not a very scientific test) showed no reduction in spring travel.

Kev, as you know, there is a big difference in the "shore" hardness between the the proper NOS Metalastic contrasonic bushes and the only alternative as supplied by JRW. I think the main issue is that the new stuff is too hard. I did buy a couple of NOS ones a couple of months back and I've fitted one to the O/S. At the moment, it seems to have settled into a position and I hope it will hold.

In my view, when Rover approached Metalastic in the 1950's to get a new-fangled rubber bush (contrasonic) made for the new 3 Litre, they would have been very specific about what stresses it would have to take as failure would not have been an option! In my view the softness of the ORIGINAL bush is designed to "give" with any movement of the spring and not resist movement although I agree, almost all original springs are now showing some degree of loss of camber so the bushes might well be under greater shear forces than originally intended.

I think the new replacement bush rubber composition is far too hard and that's why there is little give and the eventual tearing of the rubber. I'm willing to bet that had you been able to use a NOS bush with your modification, you would have ended up with a very long term solution.  

[richardlamsdale]

May 7, 2015 12:37:32 GMT @resurgam said:

May 7, 2015 9:31:37 GMT @kevbacon said:

I use a similar small bottle jack when changing mine.
When tidying out the sheds I found one of the mounts I started making a few years ago.To my mind these Y mounts need to be comparatively stiff if they are to modify the behaviour of the leaf spring as per the text on 'contrasonic springs. If they are soft they wont. I think the replacements fail because 1 they are fitted to springs that have already settled and are thus under constant shear stress and 2 they are two soft in the first place.
I fitted my mount (which uses stiff Land Rover engine mounts) temporarily to judge the effect on my springs which although old still have some curvature.The ride height was increased by a couple of inches.Bouncing the car up and down by jumping up and down on the bumper(admittedly not a very scientific test) showed no reduction in spring travel.

Kev, as you know, there is a big difference in the "shore" hardness between the the proper NOS Metalastic contrasonic bushes and the only alternative as supplied by JRW. I think the main issue is that the new stuff is too hard. I did buy a couple of NOS ones a couple of months back and I've fitted one to the O/S. At the moment, it seems to have settled into a position and I hope it will hold.

In my view, when Rover approached Metalastic in the 1950's to get a new-fangled rubber bush (contrasonic) made for the new 3 Litre, they would have been very specific about what stresses it would have to take as failure would not have been an option! In my view the softness of the ORIGINAL bush is designed to "give" with any movement of the spring and not resist movement although I agree, almost all original springs are now showing some degree of loss of camber so the bushes might well be under greater shear forces than originally intended.

I think the new replacement bush rubber composition is far too hard and that's why there is little give and the eventual tearing of the rubber. I'm willing to bet that had you been able to use a NOS bush with your modification, you would have ended up with a very long term solution.  

What a strange coincidence - one of the old shackles on my car looks exactly like the one you made Kev, with the band around the middle of the rubber and the bolts on the inside of the steel triangle. I managed to get both springs off last weekend for re-conditioning, and will replace all the bushes.

I didn't recognise what the mount was at the time, other than it didn't look standard, but it must be a pair of Land Rover engine mounts that a previous owner fitted. It looks like it's been on for some time - certainly quite a few years, and passed the MOT again this year, whereas the other one (looks original) failed as it's split.

My springs are very flat, with the shackle under constant shear, so I'd suggest that the engine mount idea might be a viable long term solution if the JRW re-made ones fail quickly. Here's a picture I took last weekend:

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[Welsh Warlock]

Its like te three bears in here - too hard, too soft or just right?

[Deleted]

May 7, 2015 13:40:04 GMT Welsh Warlock said:

Its like te three bears in here - too hard, too soft or just right?

As the actress said to the Bishop

PS, wasn't it actually too hot, too cold and just right

[Phil Nottingham]

I do say use SEARCH.  I had a pair of Wadhams LR mounts on one of our P5's for 15 years.  I bought them in 1992 and that was all was supplied 2 mounts. I had to drill the triangle mounts and assemble. They were fitted with new springs and they had settled back to the level of the old ones I took off by then.  A pair of Wadham's LR mounts from 1998 are still on the Coupe and they look alright but then it has not been on the road since 2009 - soon though I hope

[Welsh Warlock]

May 7, 2015 16:20:39 GMT @resurgam said:

May 7, 2015 13:40:04 GMT Welsh Warlock said:

Its like te three bears in here - too hard, too soft or just right?

As the actress said to the Bishop

PS, wasn't it actually too hot, too cold and just right

You need to check your facts: The porridge was too hot/cold/right, the beds were soft/hard/right

So yes and no.

[Deleted]

When I get a chance I'll make some adjustable triangular mounts to take these heavy duty engine mounts. The rubbers have to be stiff to modify the behaviour of the leaf springs,as per the original design. Too soft and they wont work,but assembled they must be under no strain at rest,other than from the weight of the car which is mainly in compression.

[Colin McA]

When I have done them inc an emergancy replacement.

Jack the car up taking the wheel off the ground. Remove the old mount. Fit the replacement. With the bar of a trolley jack or similar in the middle of the triangle pull down and tease the bush into place.

When it is in the rest is obvious.

I have used the landrover mounts, £10 on ebay usually covers them, I have a spare set in the garage.

Colin

[Deleted]

May 8, 2015 7:57:50 GMT @kevbacon said:

When I get a chance I'll make some adjustable triangular mounts to take these heavy duty engine mounts. The rubbers have to be stiff to modify the behaviour of the leaf springs,as per the original design. Too soft and they wont work,but assembled they must be under no strain at rest,other than from the weight of the car which is mainly in compression.

All I can say Kev is the NOS Metalastic ones I have are soft and pliable.The only other person I know who has an original "Contrasonic" bush is Phil.

[enigmas]

I'm missing something in following this train of thought! How much deflection, both fore and aft does anyone believe that these bushes have to accommodate during normal driving conditions. Given that consideration what type of rubber would best suit this bush? (Wouldn't the way to setup these bushes be...in a neutral or no deflection position, when the car is on level ground with perhaps 1/2 a tank of fuel and the weight of perhaps 2 occupants in the front seat.) If the bushes were positioned in a neutral position, it would then be irrelevant whether the springs were mildly/steeply or even arched at all as deflection both fore and aft would be balanced.

[jtw]

May 8, 2015 8:15:37 GMT Colin McA said:

When I have done them inc an emergancy replacement.

Jack the car up taking the wheel off the ground. Remove the old mount. Fit the replacement. With the bar of a trolley jack or similar in the middle of the triangle pull down and tease the bush into place.

When it is in the rest is obvious.

I have used the landrover mounts, £10 on ebay usually covers them, I have a spare set in the garage.

Colin

Hi Colin
Two things here,you are a lot younger and fitter than most of us, so that helps and secondly the made up bushes have two nuts welded to each side of the triangle to hold the screw in mounts. You also have the head of the studs sticking up from the botom and the studs are longer than the originals. This makes it more difficult to get a reasonable sized bar up the middle of the triangle. I had various bars and screwdrivers etc. and could not get enough clearance to wiggle the bush out.
   The Vauxhall jack is very low when wound down and allows you to get quite close to the end of the spring, thus requiring less effort to push the spring down, putting a lot less stress on everything.

  I'll carry it with me in future and let you borrow it if you hace anothe emegency  or Cyf  has.


   JTW

[Deleted]

Agreed the Bush should be fitted so under normal conditions it is not under fore and aft stress. I think the original rubbers spec is no longer known or repeatable in modern replacements.

[Deleted]

May 8, 2015 10:09:40 GMT enigmas said:

I'm missing something in following this train of thought! How much deflection, both fore and aft does anyone believe that these bushes have to accommodate during normal driving conditions. Given that consideration what type of rubber would best suit this bush? (Wouldn't the way to setup these bushes be...in a neutral or no deflection position, when the car is on level ground with perhaps 1/2 a tank of fuel and the weight of perhaps 2 occupants in the front seat.) If the bushes were positioned in a neutral position, it would then be irrelevant whether the springs were mildly/steeply or even arched at all as deflection both fore and aft would be balanced.

There is no built-in fore and aft adjustment with the bush although final tightening isn't done until the car is back on the ground.The two studs are a close fit in the spring and the shackle locating studs are a close fit in the slots.

Until someone fits a camera under the car and records the movement of the spring at the "contrasonic" end, we don't know how it moves with the spring.

I firmly believe that Rover specified exactly how they wanted this component made up and would have expected metalastic to produce something to Rover's exacting standards and it would not be expected to fail under any loading conditions.Many people on here are full of admiration for pre-BL Rover, so it is highly unlikely that anything was left to chance although, as I've said many times, the original springs on most cars are bound to show some loss of original camber.

I was very lucky to get the NOS "contrasonics" but let's see what they look like this time next year although I've only done the O/S ATM. 

I've got a spare JRW bush just in case.

 

[Warwick]

May 8, 2015 10:09:40 GMT enigmas said:

How much deflection, both fore and aft does anyone believe that these bushes have to accommodate during normal driving conditions.

My drawing shows the distances.

[enigmas]

Truly Resurgam it's not that hard to gauge movement. Simply have a friend stand on the rear bumper and 'pogo' the back of the car. Unbolting the bottom shocker mounts will assist in this.
As for the technology for producing rubber or synthetic products for this type of function, it certainly hasn't evaporated into the ether or into a contemporary Dark Age. Companies like McKay Industries still produce an amazing range of products for all types of machines/equipment/automotive and marine requirements. The company is 2 mins from my home and has been in business since the 1930s.
The remanufacture of the subframe isolation bushes are just one example of what can be done if the desire and support is there.

McKay Industries

Take a look at p2 of 3. The domed Isolators. Current technology like these could be adapted to a rear mount.
High Deflection Isolators