Specifications for the Sierra Rear Suspension Outer Bush Bolt

[ForumGuru]

Hi,

My Ford Sierra's rear suspension's outer pivots seem to have a lot of flex in them. (on a monocoque chassis, where it is the part that is visible from the side). Could someone kindly provide the bolts and holes' measurements and other information?

Cheers

[CyberNinja]

Do the nuts and bolts really wiggle? Most likely, the suspension arm has worn bushes.

[ForumGuru]

Yes, the bolt heads do move when accelerated.

According to what you say, the bolts are intended to help you find the bushes, not to keep things tight. So there's supposed to be some movement between the bolt and the hole when the bush flexes? Do I have the proper idea?
 

[CyberNinja]

The nuts should be tight because they squeeze a metal tube inside the rubber bush. Pull them as tight as you can and check to see if they still move.

 

If they're not tight, the holes in the back beam may have gotten bigger. The simplest way to fix this would be to weld a thick screw over the hole in the beam.
 

[ForumGuru]

Thank you very much. So the diameter of the bolt should be the same as the diameter of the hole (mine are around 2mm wider than the bolts). And if the holes are too large, do I need to weld washers on from the outside or from the inside?

Another question to ask to ascertain if the bolts were proper in the first place: what should the bolt diameter be?
 

Edited July 1, 2023 by ForumGuru

[CyberNinja]

I'm pretty sure that the nuts should be 10mm. I'm not sure if the mono structure, but I think the bolt only goes through the Sierra beam. Most likely, both ends of the bolt need washers.

 

Can you post some pictures?
 

[ForumGuru]

This is distinct from the conventional 11 or 12mm fasteners.

Yes, after I get home Sunday evening I can get some photos. So perhaps Monday evening following work. Thanks again.
 

[WiseSage]

Metalastic bushes, as far as I can tell, are meant to be screwed down securely, with the rubber bushing taking care of the wiggle room. To avoid "pre-loading" the bush, it is recommended to not completely tighten fasteners until after the vehicle has been returned to its usual driving position.

 

When using poly bushes with a metal sleeve, the tube must be tightened such that the bush spins on the sleeve and not the bolt. To prevent the bush from being clamped when the bolt is tightened, the sleeve should be a millimetre or two broader than the bush.

 

I suppose I just always did that.

[ForumGuru]

So, to summarise:

These are metalastic shrubs, which consist of an interior tube with a rubber bush bonded to it and a metal case bonded to the outer surface of that.

* The nut secures the tube to the'shackle' on the rear subframe. Consequently, the tube does not move relative to the subframe.

* The casing is pressed into the rear arm.

* The suspension movement is only possible due to the flexing of the elastomer. All metal components are rigid.

 

Two images:

There are two'shims' installed here, which makes me question whether the fastener is the correct measurement. The head of the bolt has begun to move relative to the metal it passes through (which I'll dub a shackle for now).

This image displays the rubber on either side of the swing arm when viewed from the front. Is this how you would envision a metalastic shrub to appear? 

[TechWhiz]

Although they are not readily accessible and are notoriously difficult to install, it is highly recommended that you get polyurethane bushes rather than these, despite the fact that they are almost identical in appearance.

 

There is a wide selection available on eBay.
 

[ByteStorm]

My previous bushes were worn and squishy, so I replaced them with RallyDesign polybushes, and the result was much firmer rear suspension.My previous bushes were worn and squishy, so I replaced them with RallyDesign polybushes, and the result was much firmer rear suspension.