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» Brakes and wheels
Engine bay work
Some easy work
:: Brakes and wheels
:: Fitting Anti-squeal Shims on 20VT
Thanks to www.coupe-sport.co.uk
Estimated time required – 2 hrs.
Tools required – Shims x 4, small tube of copper grease, gas pliers, 4mm drill bit or equivalent, partners toothbrush, brake cleaning fluid or equivalent, small hammer, std Fiat jack and toolkit.
Park the car on level ground with the steering wheel fully clockwise. Switch off the engine, apply the handbrake firmly and put the car in gear.
Jack the front driver side of the vehicle up and remove the wheel.
[see picture 1]
With the wheel removed calliper access is good and the pads can be clearly seen inside. The pads are held firm by two pins and a spring clip. The pins and spring clip must be removed before the pads can be withdrawn from the calliper.
[see picture 2]
The pins can be removed by gently tapping them out of their locations in the calliper with the aid of an old 4mm drill bit or equivalent and a pin hammer. They will emerge out of the back of the calliper.
[see picture 3]
With both pins withdrawn out of the back of the calliper, the spring clip is free and can be easily removed. If the pad wear sensor wire is still connected to the wiring loom on the car (few are) then disconnect the plug and ease the wire out of the calliper slot so that it hangs free.
[see picture 4]
It is possible at this point to just pull the pads out from the calliper. In most cases though it is helpful to push the pistons back a fraction so that the pads become loose (this will also help when it comes to re-inserting them with the shim in place). This can easily be done by using a pair of gas pliers, locating one of the jaws on the metal pad backing and the other jaw on the outside of the rear of the calliper. The piston should move in pretty easily and requires little force. You may even be able to do it with your hands if you don’t have any suitable pliers.
[see picture 5]
Do the same for the other pad. It’s a good idea to put a bit of tape along the edge of the calliper to protect the lacquer from the jaws of the pliers.
[see picture 6]
The inner and outer pads can then be simply pulled out from their locations. In some cases, the pads cannot be withdrawn as easily as they should, due to corrosion forming underneath the stainless steel pad guides which are not easily serviceable (see picture on next page). If the pads do not withdraw easily then they may have to be pulled out with some force with the aid of pliers.
[see picture 7]
With the pads removed, the side profile of the pads should be reduced slightly with a file so that they can be slid in and out of the callipers with ease. Failure to do this could possibly lead to warped discs and further brake squeel. With the pads removed, the next job is to give the inside of the calliper a thorough cleaning. I do not recommend the use of a wire brush as it can easily damage the dust seals around the pistons. Instead I used the wife’s toothbrush and some citrus degreaser! If you don’t have any degreaser then you can buy a commercial spray-cleaning product, but warm soapy water is probably adequate. Get the toothbrush into all the areas inside the calliper and especially around the stainless steel guides, which sit at the top and bottom.
[see picture 8]
Stainless Guides Some pads have a rubbery backing on the metal part which, if peeling off, may stop the shims being as effective as they should (the shims rely on a long term interface of copper grease between back of pad and shim). If this is the case with your pads then I would advise scraping the backing off before proceeding. Give the pads a good wipe with a cloth to remove any old brake dust and grease, then apply new copper grease to the rear of the metal backing.
[see picture 9]
Spread the grease around so that it covers most of the rear of the pad. There should not be so much grease so that it will ooze out when the shim is in place, but you do want a good layer. Take care not to get any grease on the front friction surface.
[see picture 10]
Place the shim on the back of the greased pad. The shim is self-locating, centering and retaining.
[see picture 11]
Apply further copper grease to the rear of the shim...
[see picture 12]
...and to the edges of the pad that will come into contact with the stainless steel guides on the calliper.
[see picture 13]
Slide the pads back into the calliper with the shims in place...
[see picture 14]
...then give the pins and spring clip a wipe with a cloth and coat the pins in a thin layer of copper grease. Fit the spring clip in place first and then push the pins through their holes in the calliper from the back of the calliper to the front. Push them home with your hands so that they just locate in the holes in the front face of the calliper...
[see picture 15]
...then tap home gently with a hammer from the back of the calliper until flush. Push the pad wear sensor wire back through it’s notch in the calliper and reconnect with connector or just make tidy with tyrap if not required.
[see picture 16]
Remove the tape from the front of the calliper and give the disc a good wipe with a cloth to remove any grease or grit. Re-fit the road wheel and repeat for the other side. When finished get back in the car, start the engine and pump the footbrake until normal brake pressure is regained before driving away. Also please note that braking efficiency may be impaired for the first few miles if a substantial quantity of copper grease was accidentally left on the discs.