Powerflex Bushings

[Splat]

FWIW, I've re-measured the internal bore of all three bushes. Both the Metalastic and PFW92 are uniformly 11.05mm, measured on several units. 7/16" is 11.1125mm. My 7/16" suspension bolts slide through perfectly.

The two PF99 units both measure up at 12.15mm. I find it inconceivable that Powerflex should list the PF99-116 unit on it's website, with a link to the technical technical drawings, as having a 12mm bore, yet supply the same part number Stateside at the 11.05mm required to be compatible with an Imperial bolt.


http://www.powerflex.co.uk/i/product_im ... %20WEB.pdf

[Westfield 129]

You are correct. I ordered my bushings with 7/16" inside bore sleeves. I believe that the sleeves were made up at Powerflex USA.

I have a second set still in the box with 12mm bore sleeves. I will make up another set of sleeves if I use them. I forgot to make the special order request...

Ordering the Westfield supplied Powerflex bushing is a better deal. Much easier.

[alleggerita]

With all these never ending discussions on bushings you would have expected that someone had tried to modify the suspension to ball joints on rod ends. Has this ever been done on here?

[jonclancy]

I'm expecting a call back from their technical development chap today.

It may be that we can sort the exact spec out and get a price for a run. WSC may want to partake to supply with the next batch of kits, but I haven't approached them yet.

What would be a reasonable price point for everyone here?

[Westfield 129]

I have seen a couple of W11s using the Stanpart uprights and ball joints from a Lotus Europa/Triumph Spitfire, along with custom made upper and lower arms. I drove one of them, and it worked well, but not better than my own Spridget king pin setup.

However, this doesn't fix the problem of the suspensin bushings... The metalistics can last for a long time up front, but in the rear, with the twist and thrust.. That's where the problem is.

[jonclancy]

... And here is the solution.

I had a very productive conversation with the Powerflex tech development chap, Paul. He has a link to Splat's post above...

Powerflex will gladly modify sleeves to the correct bore and length. Plus will trim the PU material length if needed.

The difficulty and expense will come if we require the PU to be re-tooled.

The WF bushes are a great size, but not compliant. If we can modify the sleeve bore, length and PU bush length of the PF99-116, then we need to order 50 pieces to get the run done under its own part number for this application.

That's three cars worth.

The PF9-116 sent Stateside with the 7/16" bore were Jan's special order, as he mentioned.

So, can we mod a current bushing to our exact requirements??

Over to Splat and Jan to sort out the dims/spec.

BTW, there are three materials: yellow, purple and black. Black being the hardest (race).

Cheers

Jon

[Splat]

Well, I'm in for a set (even though I've just purchased the suite of 18 from Westfield!). My preference would be for the PF99-116 bushes, modified to suit. So, the same thickness of PU in purple, giving good compliance and a more comfortable, less crashy ride over our horrid roads. The PU tubing they already manufacture, it only needs to be cut to the correct length. Likewise the washers remain unaltered. All that needs producing is the centre tube, bored to 7/16" and cut to the correct lengths. I can give Paul the dimensions tomorrow (I have his email address). All that's needed is enough expressions of interest here............

[Splat]

It just so happens that I set about extracting the old Metalastic bushes from the trailing arms this afternoon. I replaced all of the bushes 2000 miles ago and know what a bitch they are to remove. In the end I gave them to our local race car engineering outfit at Thruxton, who pressed them out in their hydraulic press in minutes!

So I knocked-up a little press out of 3" timber and a G-clamp. But the seasoned pine started to crack before the first bush had shown even the slightest sign of movement

The only realistic answer seems to be hydraulic, although brute force and a hacksaw is another solution.

However.....

.....last time I installed the trailing arms using the Jan method of "don't torque 'em" and after 2000 bumpy and fast miles the bushes in the one arm that I removed look brand new! So for the moment the arm's going back in untouched. Having said that, if we can get PU bushes of reasonable compliance manufactured, then I'll definitely be swapping to them for the longevity and improved ride that they should provide.

Meanwhile, I'm hoping that tomorrow will see the return of my diff from Heathrow Transmissions, complete with the Quaife ATB lsd that I bought from Demon Tweaks (they're currently offering 10% off).

[Westfield 129]

What you want to use to press the bushings into place is a hydraulic press (available here in the US for around $110 from Harbor Freight). However, it may be difficult to get the front lower arms into any press. Some gymnastics are required with the part to get them to fit in the press to both remove and install the metalistic bushings.

Hudraulic presses are pretty dumb tools, with no precision threads and a simple sliding frame with a hydraulic bottle jack. They are not expensive and even a cheap one will do the job on most applications. The problem comes with the frame design, and its ability to swallow the part you need apply pressure to.

OR, a proper bench vice can be used to do the job. This is actually easier to use on the front lower arms.

A largish bench vice with a 6" throat or bigger (so you can fit the bushing and a fixture to press it into place (a piece of pipe or a socket), and a nice long handle to ease the effort.

Interestigly enough, a press may be less expensive than a proper machinists vice, but you really need both.

BTW, the more you change the bushigns, the easier it gets. Don't forget to grease the shells prior to installation, clean the insides of the arm's sockets and apply lubricant. Make sure that the edges of the arm's sockets are not peened over, making the initial fit a bit too tight.

Installing the Powerflex is pretty easy. I used the bench vice to do mine.

2000 miles is not bad. I think that adding the Powerflex bushings to the chassis end of the trailing arms can extend the life of the axle bushings to 3000 miles or more.

[jonclancy]

I'm in for a set of 18....