MICK’S TIPS

BRAKING NEWS

IF YOU’RE a home mechanic who likes to fix your car, let’s talk about the job of changing your brake pads. On a modern car, when you go to release t he ca liper, you’ll notice it’s sitting on a bolt with a mount system and the assembly is known as a ca liper pin or ca liper slide.

Now what a lot of people forget to do when they’ re changing the pads is to remove the pins completely and clean them – free them up of all the road grime. Then apply a little rubber grease or anti-seize.

In fact here’s a tip: when you’re buying t he pads, see if you can also source a new set of the rubber boots that go on the pins. What happens is they perish, the road grime gets in, attaches itself to the grease that’ s in t here and turns it into grinding paste. The down side is t hat, because it’s a single-acting ca liper in most cases – so only one side is applying the pressure via pistons–it requires very good free movement for both sides to disengage properly once you take your foot of f t he pedal.

Now the problem becomes t wo-fold: f irst t he pins themselves get worn probably faster t han t hey should; And the bra kes tend not to f ully release. With t he pads stay ing engaged, you get over-heating, which in turn warps t he discs. The whole system ends up unhappy, as you’re apply ing more pressure to get the bra kes f unctioning properly and in turn t hat’s piling on extra wear and tear.

Now we had exactly this happen to Ed Guido’s E39 BMW 540 Sport. The workshop that last changed t he pads and discs didn’t go to t he extra trouble of refreshing t he pins. So t he inev itable happened. The pads weren’t getting t he usual k nock-of f or suck back, and therefore were contacting the disc more than they should. Then the disc overheats and warps. The car developed bra ke shudder and the discs had to be machined far sooner than you would normally expect.

That’s not t he end of t he world, but it’s a nuisance and an unnecessar y expense. The moral to the stor y? Do the whole job and not just a quick pad shuff le. It may ta ke a litt le longer, but t he bra kes will work a litt le better, plus it saves time and hassle in t he long run. Good luck…

Note: Mick runs Glenlyon Motors in Brunswick, Vic. Tel(03)93805082.