Nolathane Diff Bush Noise Fix?

[seduced]

Just pumped 2 cartridges of sikaflex 227 into the top crossmember which the rear centre support welds onto. I'll let it set for a few days and report back any differences. I reckon I'll need alot more....

While I was under there, I noticed there was a piddly little rubber washer for the diff cradle bolt... However nothing between the cradle and the support at all... Ford: Whats the point of a rubber washer there? That would make ZERO effect to reducing vibration.

By the way, this cross member that I filled welds directly underneath the boot floor plan (the flat part right behind the rear seats inside the boot)... every single vibration from the driveline is transferred from the diff cradle to the support bracket (no bush, just that stupid bolt) then that braket is welded directly to the cross member, and then your boot is welded to that cross member. Its a direct path for noise into the cabin.

Further more, if you dont have any sound dampener in your boot, it will amplify these noises and vibrations as its basically a big steel drum...

Edited 11/11/09 04:55 AM by seduced

[Guest STEVE_BAXR]

Steve - Was thinking of filling the hollow mounting blocks with SikaFlex227 for vibration absorbtion. Also, Rubber pad between bolt and frame, and also vibration deadening on the entire crossmember, support bracket (the one with that stupid bolt) and accross the entire rear diff cradle. If I can stop the vibration at the source, it will mean less noise transferred. Therefore less noise to dampen in the cabin.

What do you reckon? Any underbody products you recommend?

Hello hello

To fill the box rail you could get some Expanding foam from Bunnings (340g PARFIX FOAM FILL EXPANDING FOAM)cheap cheap and get some sound pads for the floor, and for the stupid bolt I was thinking of making a bush up .

It needs to be free like the diff bush no metal on metal eg photo, make some think up to hold the bush then put the bolt in.

But the only noise I get now is just the some road noise no more diff bush noise, if you have eg 20"or 19" rims low tyres you will get road noise every day that's life. all cars have some road and wind noise just that the diff bush noise was real bad on the ear's.

[Guest STEVE_BAXR]

I have just put a new diff bush in and I have to say the noise is bad , so I had to have a look to see why ? there has to be a fix for it.

I am a BMW panel tech and the BIG thing that BMW is good with is no noise in the car . The nuisance noise that occurs in these pillars is related to power train, wind, tire, and road noise. Over the years, various solutions have been used to minimize the energy level of noise that flows from these sources to these pillars. A current approach is to block the path of noise with heat reactive, expandable sealing materials mounted to support plates to create a"baffle". Baffles are strategically located within the body structure in a pattern that helps to eliminate propagation of noise into the vehicle passenger compartment.

The good and bad news is to save money ford don't put any acoustic baffle or sound pads in but to stop the noise but we can.

The big part that makes all the noise in the BA is that the boot floor is like a dum , The nuisance noise come's from the diff into the diff bush then into the body. If you have a look under where the diff bush is there is a metal brace going to a nice matel box, and in the box is air NO EXPANDABLE ACOUSTIC BAFFLE ..... thanks ford .

So in the next week I will be looking more into it and filling the air with expandable sealing foam and adding some sound pads to the boot floor..

As I said its just a dum in the boot and for the sikaflex it could be like the old diff bush TO HARD so the sound will get bad you need a soft sound baffle.

[seduced]

Sikaflex 227 is super soft. Far softer than any rubber in any bush. I will try expandable foam as well anyhow.

I have since dynamatted the boot well with about 50% coverage (which is all you need) and that has reduced the noise considerably. My main problem is that I have a diff whine at 105-115km/h. Ford says it is normal to have some whine in these diffs, and mine is not anything to be worried about. They could hardly hear it. Other passengers don;t hear it either, I'm just super picky.

Anyhow, I believe that bolt would be the main transfer point for diff noise, so I'm looking into some options there. I also have some serious professional sound absorber and barrier material that will go in to futher cut road and all driveline noise.

I also scored a chassisEAR diag system. In the next few weeks I'll be hooking it up to several points around the rear to find the culprits.

[jacob_xr6turbo]

so.. should I do this diff bush replacement through the boot or take it to pedders with a fulcrum bush and tell them to replace it..

decisions, decisions..

well done on all the information in this thread steve, invaluble!

Edited 03/01/10 07:59 AM by Christiaan

[jacob_xr6turbo]

hey guys

so this is the bush I need to order? SPF2654K

it says for competition use, etc, but this is the bush youre using steve? with little or no NVH?

Thanks guys,

[senna_T]

Chris, you want SPF2654-70K - I got em in stock right now bud!

[SavageF6]

To add to this thread, I'm going with the BF Superpro comfort option from senna_t (part no. SPF3232-70K)

http://www.fordxr6turbo.com/forum/index.php?showtopic=66448&view=findpost&p=985218

Edited 25/02/10 05:58 AM by SavageF6

[Rudiger]

How much and whos fitting it for you??

[bf xr6 turbo]

hey all,

great thread I am just about to get my diff bushe done and it was going to cot 440 in labour cause they were going to drop the rear end out but with this I should be able to cut that labour cost in half and next time I can do it myself. would do it myself this time but the boys at AVO are giving the old girl a little bit of a tickle while she is there