MICK’S TIPS

FIX THOSE BRAKES

Unique Cars - - CONTENTS - MICK MCCRUDDEN

WE HAD A LOOK at brake f luid back in is­sue 406 and this time I reckon we should look at the hard­ware. Check­ing out disc pads is easy – you can gen­er­ally grab a torch and sight along the disc. As for drums, there’s no way round it, you’re go­ing to have to pop off the wheel and the brake cover. As a gen­eral rule you don’t want any­thing less than 2mm of ma­te­rial.

When it comes to disc brakes on older cars, most peo­ple are up to speed on the ba­sic tech­nolog y. For your old Ford, Holden or Valiant, you’re work­ing with PBR or Gir­lock or sim­i­lar, with a mas­ter cylin­der un­der the bonnet, a vac­uum booster, with a sim­ple caliper and disc at the other end.

Let’s say you’ve got ac­cess to the caliper to change the pads and give it a gen­eral check-over. When you go to push back the pis­tons, a proper push­back tool is ideal, but a G clamp or sim­i­lar used with care is just fine. In­spect it thor­oughly and give it a gen­tle clean out. What you’re look­ing for is any sign of f luid leaks. If there are, it’s re­build time. This isn’t nec­es­sar­ily a huge job, but you need to be sure you’re us­ing the cor­rect and good qual­ity com­po­nents. Re­mem­ber your life might de­pend on it!

There are some very good change-over and re­build ser­vices out there (such as Power Brakes, which fea­tured in last is­sue – Ed.) who can do it for you quickly and it gen­er­ally doesn’t cost a bomb. It’s al­ways worth con­sid­er­ing as a pre­cau­tion­ary mea­sure, par­tic­u­larly on a restora­tion. It makes the whole assem­bly job eas­ier and cleaner, and you know what you’re start­ing with.

It’s easy to ac­ci­den­tally pop the pis­ton out of its cylin­der and get­ting it back just re­quires a lit­tle pa­tience. They’re a tight fit and need to be wig­gled back into place. What you don’t want to do is force it and dam­age the work­ing sur­faces.

Pop­ping the pads in is very sim­ple. Hope­fully you’ve taken note of how they were in­stalled when you pulled them out – in­clud­ing any re­tain­ing bolts or clips. And here’s a key tip: don’t for­get to pump the brake pedal once it’s all to­gether again to get your nor­mal pedal feel back. There’s noth­ing worse than tak­ing off and find­ing no pres­sure in the lines !

Just be aware that some later model cars have a screw-back rather than push-back sys­tem for the rear pis­tons. If that’s the case, it’s best to have the right tool. A set of multi­grips will do at a pinch, but you risk do­ing dam­age. One easy way to check whether it’s screw­back is look for a handbrake lever on the back of the caliper.

Older solid discs are gen­er­ally de­signed to be ma­chined to refresh them if they need it, but only to a cer­tain point. Gen­er­ally, the min­i­mum ac­cept­able thick­ness is stamped on them. If you’re near the min­i­mum, shout your­self a new set – they’re not worth the gam­ble.

With later sys­tems, par­tic­u­larly Euro­pean cars, you’ll no­tice the black brake dust that seems to get lib­er­ally spread over the wheels – that’s a fair in­di­ca­tor you’re deal­ing with a set-up where the disc is de­signed to wear quickly along with the pads. The per­for­mance and feel is ter­rific but, in­stead of ma­chin­ing them, you’re gen­er­ally deal­ing with a dis­pos­able item and they’re priced that way – of­ten a third of the cost of a more ‘tra­di­tional’ part.

If you’re work­ing with multi-pis­ton sys­tems, just be aware you need to be able to push back all the pis­tons at once and that’s where hav­ing the right tool is a big help.

Drums are a lit­tle more labour-in­ten­sive to work on – or at least to get ac­cess. Once you’re in there, you’re look­ing for: no leaks from the wheel cylin­der, good thick­ness on the shoes and drum it­self, and even wear.

If the drums are squeal­ing it’s of­ten be­cause they didn’t ra­dial grind the shoes and match them to the drum, so the wear is un­even and you’re work­ing a smaller area. Peo­ple used to do all sorts of things to stop the noise, such as springs around the out­side to stop the har­mon­ics, but ba­si­cally it’s a mat­ter of set­ting the brake up cor­rectly.

If you’re out there restor­ing a car with a drum brake rear end, it’s crit­i­cal you get the right-sized wheel cylin­der and match the shoe to the drum. Drums and shoes can be re­con­di­tioned/re­lined, but it’s a pro­fes­sional job.

Now here’s my fi­nal bit of ad­vice: don’t be a cheap­skate. Brake com­po­nents have come down a lot in price over the years and this is one area where I re­ally won’t take a chance – too many lives at stake. So if I’m not us­ing orig­i­nal equip­ment, I’ll go for known brands such as EBC, Bendix, PBR, Lu­cas/Gir­ling and so-on.

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