Bush Changing Time

[Guest jasonmorris]

Right people, this is it, over the next couple of weeks I am going to change the rear suspension bushes on my series two.

 

The main reason for tackling this job is that as some of you may remember my rear suspension has been knocking for some time. I finally traced this to the nearside outer bush and the fact that the crush tube is no more. This has in turn worn an egg shaped hole in the mounting bracket and will not tighten (is loose after every short run).

 

Anyway to cut a long story short I have decided to do the wise thing (as originally recommended by Nigel) and change the whole lot (bushes) at once by dropping the whole of the standard sierra rear suspension setup.

 

I just know that the biggest problem I am going to have is removing the bolts that hold the outer swing arm pivot points in place. There is a bracket that is bolted to the floor of the monocoq chasis under the seat, and the bolt goes through this bracket, then through the trailing arm. The problem is to remove the bolt I have to remove the bracket and this is proving an extremely difficult task to do.

 

As mentioned my suspension is standard sierra and I would dearly love to know if there is a tried and proven method for at least lowering or dismantling this setup so I can change the bushes.

 

Any advice is greatly received.

 

Jason

[Guest jasonmorris]

Also does anyone know of a kit available to change the rear suspension to IRS?

 

Would I need to speak with a specialist such as Z-cars?

 

Jason

[Andy Spencer]

I don't think the series 2 is that different to the series 1 S7 and I did my old one OK without removing the brackets. Is it just that you cannot get the bolt out? If so, cut it off and replace from the other side - that's what I did. You should probably replace the bolts anyway.

Never took the whole rear suspension off - just removed wheels and driveshafts and took the rear trailing arms off. A lot easier to drill or turn the old bushes out then as well.

 

Andy

[Guest Alex Spratt]

Also does anyone know of a kit available to change the rear suspension to IRS?

 

Would I need to speak with a specialist such as Z-cars?

 

Jason

 

if you have the sierra rear suspension then you already have IRS! But i'm guessing that you mean double wishbone? i would like to do this (myself) on my 2B but not straight away.

Does anyone know how heavy the rear suspension unit actually is? As people are posting the axle weights with a rear bias this seems crazy with the pinto being a cast iron block and head!!!

[Bob Tucker]

As you say the engine is heavy, but it sits much further back in a Hood than a Sierra.

Also the bellhousing is heavy,

the gearbox is heavy,

the rear DeDion set up is heavy.....

the battery is heavy (but just for a few misguided types, eh Bill )

 

The bias is genuinely to the rear, about 45% front 55% rear

 

I have also looked at fitting a proper wishbone rear set up, but there are no suitable pickup points on

the 2B chassis. It would need some serious structural re-engineering to make it possible, & I decided that it would be easier to start again with a different car, probably MNR or MK.

 

Cheers, Bob

[Guest timswait]

Look at the car from the side and you'll see the engine is actually pretty much in the middle of the car halfway between the two axles, with the box and driver and other heavy stuff even further back, so the front rear split is about 45/55 on my 2B, which is pretty much ideal for a rear wheel drive sports car.

I've not heard of any double wishbone rear conversion kits for any models of Hoods. You could fabricate one yourself, I briefly toyed with the idea for my 2B. However I think the weight saving would be minimal, the improvements in geometry would not be massive and it would be a heck of a lot of work. The Sierra IRS isn't really that bad. (it's also not DeDion )

When replacing your bushes you might want to consider urethane ones. It's a mod I've been meaning to do to my car for ages. I've also heard that the easiest way to get rid of the old ones from the trailing arms is to burn them out with a blow torch.

[Guest jasonmorris]

Thanks for the advice guys,

 

to answer Andy, I have tried to remove the bolt for the mounting bracket but it is longer than the gap between it and the monocoque tub, so it was obviously put in somehow prior to mounting.

 

with regards to putting it in from the outside, the problem here is that I have about a half inch gap before the outside of the stainless bodywork to get the bolt in, and with bending or cutting it simply isn't possible.

 

Should I cut the bodywork to allow entry from the outside?

 

Any suggestions?

 

Yes, I am planning to use Poly bushes I presume this is what you mean by Urathane?

 

Jason

[Andy Spencer]

Heard that some of those bushes don't last long....think Jim had to replace his very quickly after changing them. What's wrong with the Ford ones?

 

Andy

[Guest ScotMac]

If you beleive the hype, the poly bushings are supposed to last 5 times as long as the usually rubber stock bushings. Also, the poly bushings are supposedly impervious to oil, dirt, ...

[Guest jasonmorris]

I have read many times on this site many times that poly bushes don't last as long but give superior handling performance. I have no problem changing them every few thousand miles or so, just so long as I know how to do it in the first place

 

Any one any suggestions with getting this bolt out? Should I cut a section out of the stainless to get access from the outside, and then put the bolt in from the outside?

 

Jason

[Guest timswait]

They're made from polyurethane, sometimes abbreviated to poly or to urethane. The standard Ford ones are made out of rubber. Rubber allows some compliance, so under load the bushes deform and the suspension geometry is compromised. The benefit is that they take some noise vibration and harshness out of the suspension, so are standard fitment on most production cars. Polyurethane ones are much harder, so the geometry stays better aligned at higher load, so you get better handling, at the cost of less good ride.

They should last as long as the rubber ones, but I do remember someone saying their ones wore out quickly....

[Guest jasonmorris]

OK guys,

 

I am now looking to order the required bushes, but it seems there are many. Does any one know which ones I need and which ones I don't? There are a couple that are fairly expensive, which I presume are the large ones that bolt the cross member to the chassis floor. I have read that these are no necessarily needed, is this true?

 

Jason

[Andy Spencer]

Yes true. Just buy the ones that fit into the swinging arms. If the series 2 is like the series 1 S7, those large expensive bushes are redundant anyway, the rear subframe bolts directly onto the chassis tub (or it was on my old one anyway!).

I paid about £20 from Uncle Henry for the 4 swinging arm bushes if I remember correctly.

 

Andy

[Longboarder]

I would still say drill the bodywork to get the bolt out of the outer bush. Remove the inner bolt and drop the front of the trailing arm. Push the bushes out with a big bolt and two sockets or burn them out with a blow torch down the crush tube. Full safety precautions!!!!!

Fit polybushes. You may need to make a repair to the bracketand re-drill a clearance hole.

 

Nigel.

[Guest old_timbo]

I was looking at Poly Bushes for the trailing arms on my 2B, but wow expensive - £100 for the set of 4 pairs from the well known names. There are some cheaper ones from Rally Design, but I'm not sure how good they are. Reading around it seems that there are different manufacturing techniques used for the expensive and cheap versions. Allegedly it's the cheap ones that don't last.

 

On a 2B you can't get the outer bolt out as it fouls the side of the body, so it would be a case of dropping the entire rear end assembly out to do it unless you made access holes.

 

Also, I stripped a rear end assembly a couple of weekends ago for the diff. and found that I couldn't get the inner bush bolt out (it comes out in the other direction to the outer bush bolt) without removing the drive flange on the diff. which it fouls.

 

At the end of the day its all such an expensive pain that I'm leaving the standard bushes in as they seem OK at the moment.