[Andygoodbloke]

Hi all
I am after a standard height, not raised PU bush set for a SJ413/Samurai/Sierra, the ones which go between the body and the chassis

I have been looking an can only find suspension bush sets in PU, has anyone found a set which doesn't cost the price of the complete vehicle. (cheaper the better)

You can get rubber mounts out of India cheap through Ebay - are they any good? Has anyone tried them - thoughts on them?

Having restored many vehicles (but first go at a suzuki SJ413) I would by choice make every suspension/ mount rubber/ bush/ rubber bit polyurethane, but they are not the cheapest and I have to find a set to purchase first.

Any help / websites etc would be appreciated

Thanks Andy

[fordem]

Andygoodbloke wrote:

Having restored many vehicles (but first go at a suzuki SJ413) I would by choice make every suspension/ mount rubber/ bush/ rubber bit polyurethane, but they are not the cheapest and I have to find a set to purchase first.

Strange, my recommendation would be almost the exact opposite - polyurethane has it's uses, and can be absolutely amazing when used appropriately, and just as easily turn a comfortable ride into an absolute nightmare. I've run poly on a Swift and that car would "out corner" a Lancer Evolution, but you got out of it with all sorts of backaches, poly on an SJ413 will limit articulation and make an already harsh ride worse.

[Andygoodbloke]

Hi Fordem
Polyurethane bushes are harder yes, so ideal to put into suspension as they don't squish out of shape, they squeak if you do not grease them. The hardness of your suspension has more chance of causing the aches as it is the job of the springs and suspension to make you go around corners and give you a comfortable ride. The Polyurethane bushes just transfer the load, they are not shock absorbers so if you are getting a sore back it may not be the bushes fault as it can be anything from the profile of the tyres to the damper rate of the suspension and how hard the springs are. Race cars are not comfortable it is like being rattled around in an empty biscuit tin. I have built rally cars including KP61 Starlets, Subaru Legacy (Liberty to the Aussies) and Impreza's, Toyota Celica's, all of them benefited from PU bushes, they were not comfortable to ride in

I have taken your opinion which is PU bushes are not suited to the body mounts of a Samurai/ Sierra/ SJ413, but I think it would be fine if you have big soft tyres, good shocks and springs, but it may come down to your goal, that is are you wanting a car to use daily, or an off road weapon? Please give me more views on the situation

Thanks Andy

[fordem]

Two comments ...

One - rubber absorbs shock & vibration - that is why it is commonly used in suspension bushes and engine mounts - it does this by flexing (or if you prefer - squishing out of shape), because poly bushes don't do this, they transmit significantly more shock & vibration.

Two - when I put the poly bushes on that Swift, it was the first of many changes - and it was the only change made at that time - springs weren't changed, shocks weren't changed, tires weren't changed - this, by the way, is an excellent way to determine what effect a modification has on a vehicle, make them one at a time. The increase in NVH was immediately noticeable, and because the bushings were the only things changed, there was no doubt as to what the cause was.

[Andygoodbloke]

Thanks Foredom
Yes you are correct rubber absorbs shock but this is the job of shock absorbers (hence the name), so the rubber is not as good to me because it is absorbing and wearing out rather than transferring the shock/vibration etc to the parts it is meant to - maybe I have a strong back. I have used PU bushes but not between the body and chassis, which is why I asked in the first place

I will keep my eye out for a cheap set of either rubber or PU

What have others done?

Thanks Andy

[Jezzer]

I’d just stick with rubber. If I need to replace mine that’s what I would be doing.

Off road the chassis and body will flex and if you end up splitting the steel around the mounts if you use a solid mount.

It’s not a body mount but I see it regularly at work with Hiace super custom rear sway bar mounts. People think it’s better to replace the old rubber bushings with PU and they end up splitting the D mount brackets in half with the added stress.


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[fordem]

Andygoodbloke wrote:

Yes you are correct rubber absorbs shock but this is the job of shock absorbers (hence the name)

If this was actually correct, then, "shock absorbers", as they are commonly called would not need rubber bushes to mount them. The term "shock absorber" is a misnomer, the correct term is a "damper", and this describes what they actually do, dampen or slow the oscillating movement of the suspension.

[Gwagensteve]

Manufacturers put plenty of time and effort into bush design including sleeves, voids, durometer etc in order to achieve the ride, longevity and NVH goals they've set. It amuses me that without any question people will throw this all out the window and fit a polyurethane bush on the basis it must be better for some not well articulated reason I suspect predominantly because they're brightly coloured. (every seen plain black poly bushes?) The advantages of poly bushes aren't advantages at all in a road car and especially a 4WD. Case in point - Sierra spring shackles crack when fitted with poly bushes because they're too rigid.

The body rubbers on a Sierra are very hard rubber and have steel facing on the conical sections. In fact, I'd be surprised if most urethane bushes are anywhere near as rigid. Sierra bodies do not float on the chassis like Toyotas.