Diy: Dummies Guide To Changing Aygo Front Brakes

[adilmon]

Hi,

I changed the front brake discs and pads on my Aygo and was surprised at how simple it was. Naturally, (disclaimer here) I accept no responsibility for your actions on a safety critical part blah blah blah.

Anyway. Brake overview

The Aygo front brakes consist of a caliper, which holds the brake piston and a cradle, which hold the pads and supports the caliper. The bolts holding the caliper to the cradle can slide left and right, which is why its called a floating caliper. The discs are 20mm wide when new and the wear limit is 18mm

Tools needed:

-Copper grease

-Wire brush

-13mm socket

-17mm socket

-T25 star bit (some have T30)

-Methylated spirit or brake cleaner and a clean rag

-Rubber mallet (optional)

-G Clamp

-Torque wrench (not essential)

[adilmon]

Here's the discs & pads, supplied by Apec

Use the jack to take the weight of the car slightly and use the 17mm socket to loosen the wheel bolts while the wheel is still on the ground. In the below picture you can see I needed to remove some aftermarket chrome wheel bolt covers

[adilmon]

With the alloy wheel removed, you can see the Caliper, cradle and disc clearly

The 13mm bolt with the rubber boot is the one holding the caliper. There are 2 bolts, which are not done up very tightly (30Nm). This pic has the socket hanging off it

Here's a picture with the caliper partially removed, revealing the brake pads underneath

[adilmon]

Once the caliper is removed, hang it up out of the way on the suspension. Be careful to avoid twisting or putting strain on the brake pipe

The Brake pads are held in place by small spring clips and can be easily pulled away by hand. (2 pads per disc)

I measured the discs, which were at 18.2mm. It still had a 20% life left, but I wanted them changed before the winter. The pads had 50% life left. The original discs (made by Bosch) must have been made from a relatively soft metal

Next use the 17mm socket to remove the cradle. This is done up very tightly (88Nm). You will find it helpful to turn the steering wheel to make room for your tools. Here you can see the bottom bolt has been loosened and the top one has the socket hangin off it

[adilmon]

Now prepare the caliper by taking the G clamp (this one is from a £1 shop) and push the piston back into the caliper. This is because the new pads will be wider than the ones you have removed

The Disc has a positioning screw, which holds it to the hub. Use your T25 bit to remove it. If the postioning screw it difficult to remove the disc will turn as you try to undo it. Put the car into 1st gear to stop the disc rotating. The disc is usually corroded onto the hub, so you will probably need the rubber mallet to encourage it off.

Clean the hub and new disc with methylated spirit

[adilmon]

Apply some copper grease to the hub to make the disc easier to remove in future

New disc attached using to T25 positioning screw (5Nm). Make sure no grease is anywhere on this. If in doubt, clean it again... twice

Even though these pads had anti squeal plates on the back (the side with the part numbers) apply some copper grease sparingly

[adilmon]

Bolt the cradle back on very tightly (88Nm). Slide in the pads onto their clips and push them up against the disc. Bolt the caliper back on (30Nm). Again, ensure that no grease has touched the disc or the friction material of the pads

To make the wheel easier to remove, add copper grease to it's mating surface. I used copper grease from a spray can. Don't apply the disc's mating surface, because you'll risk contaminating the important bits with grease.

Bolt the wheel back on, lower the car and you're done. The tightening torque is 103Nm, which is very tight. Tighten the opposing Bolts (eg, left-right, top-bottom)

Note: With the other side of the car there wasn't much clearance for the G Clamp and it wouldn't go into the piston straight. So I used a large socket as a shim. Pushed the piston back, problem solved

Like all brakes, the pads will need to bed in. This means no heavy braking for the first 200 miles. There should be absolutely no vibration through the steering wheel while braking. BTW, if you brake while your foot is on the accelarator (aka left foot braking), the engine check light will come on

[adilmon]

(next Aygo HOW TO will be; "How to change Diesel Aygo Fuel Filter" and "How to Change Aygo gearbox oil")

[zakelwe]

Excellent work. Thanks for posting. Just to mention that make sure the car is secure when jacked, maybe chocked and using a proper hydraulic jack.

Can I ask how many miles it took to get to that level of wear and also what sot of driving that was. I fet the feeling from your comment about the soft discs is was not that much? How much did the replacement parts cost roughly?

Regards

Andy

[Leeky]

Good guide, but there is a much much quicker way to change discs/pads.

Get a 17mm socket. Use this to unbolt and remove the wheel. Then use this to unbolt the two bolts that hold the caliper onto the hub.

Using the handle of the socket you can lever the old pads apart without having to even look at a g-clamp.

Old pads out, new pads in with a bit of copper grease.

Knock the old disc off, pop the new one on.

Bolt the caliper back on the hub and pop the wheel back on.

Time Taken - 5mins ;)

Shouldnt need a wire brush or any cleaning fluids, the aygos are way too new to have any real corrosion.

zakelwe - The standard jack will be more than safe enough to do this job. The aygo weighs hardly anything and i have used the stock jack on much heavier cars to do the exact same job.

[gordonh]

When working under my older cars (not done it for a while) I always used to put the wheel I'd removed under the edge of the car incase the jack fails.

[Parts-King]

Whenever you have a wheel off an axle ALWAYS chock the car and use something to stop the car crashing down on you Ideally your car should be on axle stands NEVER rely on the standard jack, no matter what weight the car is, they are too flimsey and with a bit of pushing and pulling at the disc/caliper it could topple off the jack, better to be safe than sorry IMHO. Have you ever tried to lift a car up when it has fallen off a jack? a right pain to get anything underneath the car to re-jack it up. Happened to me after having a puncture on the motorway many years ago in an Audi, pulled over, loosened the wheel, jacked it up, took the wheel off and CRASHHHHHH the threads stripped in the jack and the car fell down, fortunatly I had the spare wheel under the sill near the front and was able to use another jack to lift it up, standard jacks CAN and DO fail

Kingo

[Unklian]

The aygo weighs hardly anything

Have your wife / girlfriend reverse one of the front wheels

over your toes whilst wearing trainers......Trust me,

it is quite heavy......you don't want it falling on you!

[Leeky]

In the ideal world you should do everything by the book....chock the car, use a trolley jack yadda yadda yadda

But i've had so many cars up the in the air over the years that im not worried in the slightest of using the standard jack.

At the end of the day if the jack is good and you've attached it properly then unless something stupid happens you wont have a car land on you.

I did my V8 swap with trolley jacks, toyota jacks and concrete breeze blocks... you do whatever you think is best or whatever you believe is safe at the end of the day.

Unklian - any one who cant get their feet out of the way when someone is moving a car should not be be allowed near a jack anyway...

[adilmon]

...Get a 17mm socket. Use this to unbolt and remove the wheel. Then use this to unbolt the two bolts that hold the caliper onto the hub.

Using the handle of the socket you can lever the old pads apart without having to even look at a g-clamp.

Old pads out, new pads in with a bit of copper grease.

Knock the old disc off, pop the new one on....

Nice one! Now that I'm familiar with the brakes, I think I'll try your method in future.

[adilmon]

Excellent work. Thanks for posting. Just to mention that make sure the car is secure when jacked, maybe chocked and using a proper hydraulic jack.

Can I ask how many miles it took to get to that level of wear and also what sot of driving that was. I fet the feeling from your comment about the soft discs is was not that much? How much did the replacement parts cost roughly?

Regards

Andy

Thx. You're welcome.

To be honest, I simply ensured the handbrake was on, since it locks the rear wheels. I usually only chock the front wheels when I lift the rear & also put it in 1st gear.

It took 40,000 miles. Driving about 60% A roads, 30% town and 10% motorway. I don't use them a lot and often use engine braking. The discs and pads were £102 all in. It's not a significant price difference to the Toyota parts, but I was not happy with the amount of disc wear, so I had nothing to loose. I still remember when a brake disc would out last about 3 or 4 sets of brake pads

APEC are well known and any PMA supplier should be able to sort you out. For the geeks out there, Apec have Eu approvals and achieved ISO quality standards. This means the parts they supply must be within 10% of the OEM specification, but I was told (by the vendor) they exceed OEM spec. At the moment, my brakes haven't bedded in and they still snatch even though I brake gently, but I'll know how good they really are soon.

[Unklian]

I did my V8 swap with trolley jacks, toyota jacks and concrete breeze blocks... you do whatever you think is best or whatever you believe is safe at the end of the day.

Unklian - any one who cant get their feet out of the way when someone is moving a car should not be be allowed near a jack anyway...

Hi Leeky......

My V8 "swap"

http://www.unklian.co.uk/v8trike.htm

Re: feet in way: talking to wife while she's in the Aygo through passenger window about

gear selection as she drives conventional auto. watched her put it in reverse (with foot on brake)

talking away, she takes foot off brake.....

"My word" I said as it rolled over my toes. Well something like that anyway.

What was your V8 swap? any pics?

Ian.

[Leeky]

"My word" I said as it rolled over my toes. Well something like that anyway.

What was your V8 swap? any pics?

Ian.

Thats awesome!

Awesome conversion :) V8 trike sounds like quite a scarey ride :D

I was the first person in europe to do a Lexus V8 swap into a MK2 Supra.

It was in august's Banzai magazine but have since sold it to a chap who lives in ireland.

[Unklian]

You just can't beat the V8 sound.

Thats how the Supra Should have been powered. Nice one.

Oops, I think this how-to has been threadjacked.

OOooooh look at an old duffer using modern language.

My last word on the V8 subject......

http://i56.photobucket.com/albums/g194/Unk...pg?t=1225618001

Wish I still had the room to mess about with "proper" stuff.

Ian.

[rgvsean]

Theres a good reason why you don't just push the pads back in with the ratchet handle on the old pads.........

You need to clean the pistons first, pushing road grit back through the seals is not a great idea.

[Leeky]

Theres a good reason why you don't just push the pads back in with the ratchet handle on the old pads.........

You need to clean the pistons first, pushing road grit back through the seals is not a great idea.

What!?

Road grit!?

How would road grit get past the seal when there is the rubber boot in the way?

Also why would you clean the piston when changing pads?...the only time the piston needs cleaning is when you rebuild the caliper with new seals...

[rgvsean]

Did I cause offence by disagreeing with you? :P

I've got 20 years working on hydraulic systems and felt you were giving bad advice, although I grant a lot of the time you may be fine doing that, it's not best practice. I'd rather show people how to do things correctly then they can take shortcuts at their own peril and not on my behalf.

It's going to take about an extra 5 minutes to clean them up, may as well while you are there with the caliper in your hand. Maybe I should of added something in about surface corrosion/pitting etc.

You can even apply special grease to stop the seals grabbing.

But hey, it's only the brakes................

[adilmon]

I'm afraid my compulsive enjoyment of daytime TV presenter's puns has forced me to pad out this thread and brake your DISCussion.

(sorry) :P

[King Orry]

Hi Adilmon:

Just a spot of advice regarding the brake pad changes; a) don't apply grease between the wheel and hub as the drive is carried out by friction between the two (not via the studs). It is permissible to lube the spigot on the hub and inside of the wheel.

Secondly, it is paramount that the foot brake is applied before moving the car once the pads are changed. This takes up any slack in the hydraulics; also check the wheel revolves without stiction once the brakes are released post road test.

Other than the above it's a superb article, very informative.

Cheers...KO

[Leeky]

Did I cause offence by disagreeing with you? :P

Offence? why would i be offended?

Just wondering what this 'magic' grit is that can get through rubber boots and attack seals

Of course its better to clean everything when doing a job....but on the basis that everything is clean i wouldnt bother being too anal about it and i'd just get the job done (properly of course, no sense cutting corners - especially with brakes) then get back inside where its warm and i can have a cup of tea ...but hey thats just me...