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  • Added on: Mar 30 2014 02:14 PM
  • Date Updated: Jan 17 2015 10:34 PM
  • Views: 16559

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1 Ratings

Ford Fiesta Mk7.5 Rear Diffuser Upgrade (ST)

Posted by Nathan54771 on Mar 30 2014 02:14 PM
Heres A Guide To Help The Removal/Fitting Of The Rear Diffuser On A MK7.5 Fiesta Zetec S To An ST  http://static.autocl...IR#/biggrin.png
These are the parts you will need/require....
£52.76 Upper Honeycomb Deflector- 1819019 (Ford Part Number) 
£63.26 Lower Primed Deflector- 1818433 (Ford Part Number)  
Both parts above can also be purchased at pumaspeed and european parts (higher cost)
£29.99 Ripspeed Twin Tail Pipe
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2x 6mm Plastic Flanged Nut
Self Tappers 6mm Or Ford Pot Rivets (Part Number:1555829)
Process (Once Lower Diffuser Part Has Been Sprayed Colour Choice)
Cost Me £50 To Have It Professionally Sprayed Candy Blue
1. Firstly getting the back of the car onto axle stands or ramps etc will help with and makes things easier with more room.
2. Then you will need to remove the pot rivets from the original diffuser, i found a 6mm drill bit worked perfect when used in the centre (be careful and take your time, so you dont push the rivet into the plastic as you drill as the plastics only soft) until the pot rivet head comes off and then the centre of the rivet can be pushed out of the hole. There's three on each side under the corner flaps.
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3. Once the pot rivets are removed you can then slowly give the diffuser a pull from corner to corner and as it starts to come away, a flathead screwdriver helps to push the tab ledge in to remove from the slot.
4. You can then fit the two parts of the new ST diffuser together, they simply align together and then tabs fit into the slots and lock it in place. 
5. Once the two diffuser parts are together you can align it to the rear of the car and start to push the tabs of the upper part into the bumper of the car, give it a gentle tap with your palm once aligned and check its all flush to the bumper.
6. You can then screw the self tappers into the holes of the new diffuser and should line up with some of the holes of the old diffuser or if you've got the original ford pot rivets (Part Number:1555829) then put them in and tighten up using a pot rivet gun.
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7. Also while there the 6mm flanged plastic nuts can be fitted to the two tabs in the centre of the new ST diffuser using a 10mm spanner or 10mm socket.
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8. Now the new diffuser is fitted and secure, give a final push to make sure its all pushed in and flush with the bumper. You can then proceed to cutting a couple of inches (the bend) from the original exhaust. I used an air grinder with a cutting disc and slowly went through it straight up.
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9. Then you can put the twin tail pipe (chosen exhaust tail) onto the straight part of the remaining original exhaust, align it until your happy with it and then tighten it up with a 10mm deep socket or spanner.
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10. Congratulations you've then got your new ST diffuser fitted and should look something like this...
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Total Cost= £196.01
Hope this helps and if anyone has any queries or questions dont hesitate to drop me a pm, always happy to help.
Thanks Again to E5GDM (He did it first) for the idea and information towards this cosmetic modification/upgrade