FRONT BRAKE OVER­HAUL

Car Mechanics (UK) - - Project Ford Fiesta Mk7 -

1

Here is what we found once the road wheel was re­moved – the caliper and disc look­ing rusty and hor­ri­ble. Although they still worked, the vi­bra­tion due to warped discs was in­cred­i­ble and pulled to the left – a seized caliper, per­haps?

2

The calipers were un­bolted from the car­rier by hold­ing the in­ner sleeve still with grips (see Photo 1) and un­do­ing the 12mm lock­ing bolts. The calipers should then come away, but ours were so rusty they needed per­sua­sion with a big screw­driver. This outer pad had seized in place.

3

Thank­fully, Ford started us­ing stain­less steel caliper car­rier shims a few years back. Even so, the iron car­rier rusts be­hind it and, as rust ex­pands, puts pres­sure on the shims and seizes the pads in place. This one needed re­mov­ing with a ham­mer and screw­driver.

4

The car­ri­ers need to come off to re­move the old disc and they are se­cured with 15mm bolts. These are torqued up to 75Nm on re­assem­bly and a dab of thread lock is a good idea. An even bet­ter idea is new bolts from Ford, as they can be re­ally rusty – only ever use gen­uine bolts.

5

Now the car­ri­ers need to be cleaned. On re­ally rusty ones like these, smack them a few times with a small ham­mer to shock off the heavy rust flakes, then fin­ish it off with a se­ri­ous wire brush – you can even paint them. Use a file to get the pad con­tact ar­eas su­per-clean.

6

Here’s an­other view of the newly cleaned caliper car­rier. It’s es­sen­tial to get this area as clean as pos­si­ble, be­cause the stain­less shims sit in here and the pads need to be able to move smoothly. It’s worth giv­ing the whole bracket a coat of satin black to hold fu­ture rust at bay.

7

The caliper moves on slid­ing pins in the car­rier. These re­quire free move­ment and must be well lu­bri­cated. As ex­pected, one of ours had seized and needed to be freed off with a ham­mer and pen­e­trat­ing fluid. It was then cleaned and greased.

8

Both of our front discs were in the same ap­palling state – like a fit­ting from on board the Ti­tanic! We sus­pect that these discs are the 2009 orig­i­nals, in which case they’ve done well, with just one known change of front pads to keep them go­ing.

9

In sharp con­trast, here’s a new Vetech disc from GSF Car Parts. We’ve used these on var­i­ous project cars and have been im­pressed. They work well and seem to last – the days when pre­mium brake names were worth the ex­tra money seem to be fad­ing.

10

Be­fore the new discs could go on, we needed to give the front hubs a se­ri­ous clean with a wire brush. If nec­es­sary, you can also use coarse wet-and-dry with ei­ther pen­e­trat­ing fluid or brake cleaner. Any rust or dirt here means the disc won’t sit per­fectly flat and you’ll get vi­bra­tion.

11

Be­fore it went on, the new disc also needed to be cleaned. Vetech discs don’t seem to be coated in pre­serv­ing oil or thin grey primer, but it’s still worth giv­ing them a good go­ing over with brake cleaner. Be­fore they’re fit­ted, lightly smear brake grease on the front hub to pre­vent rust.

12

Here’s the new disc fit­ted – there is no re­tain­ing screw on these – then the caliper bracket can be re­fit­ted. The stain­less brake pad re­tain­ing shims have been re­fit­ted as well – be­fore you do this, smear brake grease on them now to avoid get­ting any on the disc.

13

This is the brake grease we used: Cer­atec grease made by Tex­tar. It’s a bet­ter idea than cop­per grease, although, used spar­ingly, cop­per grease is OK. You’ll find that some brake pads will be sup­plied with a sa­chet in the box.

14

Al­ter­na­tively, leave the stain­less shims clean and dry, and brush a lit­tle brake grease on the outer ‘ears’, as seen here. A me­chan­ics’ pet hate is hav­ing cop­per grease ab­so­lutely ev­ery­where as it can get onto the brake disc.

15

The new pads were now fit­ted, mak­ing sure they slid up and down eas­ily on the stain­less steel shims. If they don’t, take them apart and find out why – some cheaper pads might need at­ten­tion with a file.

16

The caliper pis­ton will now need to be fully re­tracted, as­sum­ing it has not seized. Ours were fine, but ex­tended pe­ri­ods of run­ning worn pads means the pis­ton is out by a long way and can rust. A dose of pen­e­trat­ing fluid can get a sticky caliper go­ing, but rarely for long.

17

Here’s our fully-re­built front brake. Even af­ter the brake pedal had been pumped up to bring the pads to bear on the disc, the disc still turned freely. Ours were orig­i­nally bind­ing slightly, which leads to over­heat­ing and the brakes jam­ming on, caus­ing a con­stant vi­bra­tion.

18

Look at the state of this brake fluid! Once it had been bled from the sys­tem and re­placed with new DOT 4, a sniff test re­vealed that it stank and was al­most cer­tainly the orig­i­nal fluid – the bleed nip­ples were all tough to undo due to ne­glect and lack of op­er­a­tion.

19

We bled the brakes out the old­fash­ioned way this time, pump­ing the pedal up and down. De­press the pedal very slowly to avoid flipping the mas­ter cylin­der seals. Start with the pas­sen­ger rear – the fur­thest away – and once fresh fluid is go­ing through, bleed the other three.

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.