Did my brake pads today

[InvaderGIR]

but some pistons have to be rotated whilst theyre pushed back in, otherwise you can he-man it with your bare hands in most cases

Aye, but the tool Halfords sell (well, the one I saw) was just a g-clamp with a metal plate welded onto one surface, so it has the same effect.

Who you calling *****, *****.

You actually got a working car yet?

No. Have to sell BMW bits, probably won't have a running car for a few months...stupid bills.

 

[Kappa]

Maybe it's a trade card thing? It was definitely just under a tenner for me!

Laser one right?

Aye, but the tool Halfords sell (well, the one I saw) was just a g-clamp with a metal plate welded onto one surface, so it has the same effect.

The one I got had interchangable plates, its a laser one also. Its weird, a thick threaded rod with a plate to push back on the carrier and the pushing end had to raised bits to grip the piston.


edit - maybe there was a simpler version for around a tenner but I couldnt see it

 

[allllec]

The one I got had interchangable plates, its a laser one also. Its weird, a thick threaded rod with a plate to push back on the carrier and the pushing end had to raised bits to grip the piston.


edit - maybe there was a simpler version for around a tenner but I couldnt see it

No that's exactly what I've got by the sounds of edit

Ahh here it is;

http://www.halfords.com/webapp/wcs/..._productId_214227_langId_-1_categoryId_165469

Was just under a tenner on the trade card!!

 

[Matthew.M]

Brakes seem very spongey now though. But i guess thats because the pads are bedding in. The surface had a red "bedding in coating" on them and the instructions said not to do any emergency stops for the first 200-300km so i hope they get a bit better.

I had the same when I switched to Yellows. Don't worry they totally change when they have bedded in - a process which took far far longer than with any other pad I have used so I was worried for a time, yours may be quicker with a heavier car though.

I still haven't used mine on the track yet, but on the road the braking power is incredible IMO. I stuck 5.1 fluid in at the same time and can't fault the setup.

However I really would think about changing the rears to match! When I asked for advice on other forums they all said having significantly different pads front/rear wasn't advisable.

 

[I get around]

and i dunno what golf you have, but chances are youll need a tool to put the pistons back in that rotates them at the same time as pushing them back.

I have a mk3 golf, I used a block of wood and a gclamp, worked fine.

Did my disks and pads a while back, dunno why most people don't do their own brakes nowadays, disk brakes are so easy to work with i find.
The most effort i had was borrowing a decent jack, I wasn't trusting the pound shop piece of **** I found in the boot.

 

[Matt82]

aah, the widow maker that vw supply in the boot. fun for all the family.

a gclamp is fine at the front, but the rears are defiantely the twist ones if yours has discs back there.

the costs of fitting discs and pads are daft compared to the costs of the parts on older cars

 

[Peter Diffey]

G-Clamp + Wood.

You should know this *****.

I raise you G-Clamp + old brake pad

 

[Dogbreath]

I have a mk3 golf, I used a block of wood and a gclamp, worked fine..

Fronts or rears? Front caliper pistons can be pushed in within anything handy; G clamp, hands, water pump pliers etc. The rears usually need to be turned whilst pushing since the handbrake self adjusting mechanism is a coarse screw thread that goes into the back of the piston.

 

[Dr Who]

but some pistons have to be rotated whilst theyre pushed back in, otherwise you can he-man it with your bare hands in most cases

Yup for the auto adjusting handbrake usually

Bah should have read last post xD

 

[Fr0dders]

went out for a nice drive last night. Went up to leeds bradford airport and just sat at the end of the runway watching the planes come in. Did some driving round today to shops and stuff and already they are noticably less spongy so im much happier now.

Also, the existing pads had no grease, and ive driven about 75 miles on the new pads so far and not a sound from them. So all good so far

and just to add my thoughts on the "windback tool" its not needed on the fronts. I just used a pair of pliers to force the piston back. Apparently according to the vec c forums however you do need one for the rears, due to the rotating thing mentioned above.

 

[saitrix]

To expand on what I said earlier MrLOL you really do need to swap the rear too. To work out the braking force a brake has you use the following equation.

Braking Force = effective pad radius x clamping force x Mu

Where Mu is the coefficient of friction of the pad. So as you can see it is a linear relationship between braking force and the coefficient of friction for the brake pad. So say like if you double your coefficient of friction, you double the braking force. Now a good OE level pad is around 0.4-0.45, whereas the yellowstuffs you have put on is 0.6.

So to put this into context for you, say like the standard braking bias is 60% front, 40% rear this will be altered to be more front biased. And that your standard pads are 0.45, or 75% of the yellows.

If for example as standard the front brakes do 600N force whilst the rears do 400N force. Now the change in Mu will alter the front brakes to 800N whilst the rears are 400N still. This means the new brake bias is 67% front, 33% rear. This really is not optimal as at the point of the front wheels locking the rears will be doing less braking than compared to the original brake bias. So to keep the manufacturers balance I suggest yellows on the rear. Wow this post has got long, I didn't mean to write so much, got a bit carried away.

 

[Fr0dders]

thanks for that. The rears are due soon anyway, i'm off on holiday in a few weeks, so i'll do them when i get back.

 

[Berger]

To expand on what I said earlier MrLOL you really do need to swap the rear too. To work out the braking force a brake has you use the following equation.

Braking Force = effective pad radius x clamping force x Mu

Where Mu is the coefficient of friction of the pad. So as you can see it is a linear relationship between braking force and the coefficient of friction for the brake pad. So say like if you double your coefficient of friction, you double the braking force. Now a good OE level pad is around 0.4-0.45, whereas the yellowstuffs you have put on is 0.6.

So to put this into context for you, say like the standard braking bias is 60% front, 40% rear this will be altered to be more front biased. And that your standard pads are 0.45, or 75% of the yellows.

If for example as standard the front brakes do 600N force whilst the rears do 400N force. Now the change in Mu will alter the front brakes to 800N whilst the rears are 400N still. This means the new brake bias is 67% front, 33% rear. This really is not optimal as at the point of the front wheels locking the rears will be doing less braking than compared to the original brake bias. So to keep the manufacturers balance I suggest yellows on the rear. Wow this post has got long, I didn't mean to write so much, got a bit carried away.

So what do you do if you change the front brakes for larger ones

 

[saitrix]

So what do you do if you change the front brakes for larger ones

You have multiple options. If you are swapping to say like an aftermarket caliper you often get choices on the size of pistons within the caliper, this can alter the ratio between brake pedal force to caliper clamping force. You might be able to get the correct to keep a good brake force ratio.

Alternatively you can alter the brake fluid pressure to the caliper in a few different ways. For example you can fit a brake pedal which connects to two master cylinders (one for front, one for rear) which allows the brake fluid pressures to be different for front and rear, thus getting the correct brake ratio. A more simple way is you can plumb in an adjustable restriction valve onto either the front or rear brakes, this does the same job as the pedal but it not quite as elegant a way of doing it.

Finally you could just upgrade the rears to match the fronts to keep the braking distribution correct. It is not unheard of though using different brake pad compounds to also help keep a desired brake bias.

 

[Cybergangster]

Did my brake pads today

Did this myself a couple of weeks ago. Like you, I'm no mechanic but my old man was on hand to help if I needed it. Was deeply satisfying saving myself the labour costs too.

All went fine and I took the car to work for a couple of days to wear the pads in. Gave it back to the missus and she complained the next day of a knocking sound. On Sunday I went to loosen the wheel nuts before jacking the car back up to have a look and 3 nuts were loose

I'd made a freak'in noob mistake! Damn lucky the other 2 nuts were still firmly in place and there was no damage to the threads. Next month - an oil and filter change... what could possibly go wrong?

 

[Matt82]

nothing

and once its done, you can feel smug about not having taken it up the rear from a garage but youll also know the right stuff is in your engine

 

[BigglesPiP]

Not replacing the disks too?

 

[Leeum]

Are these the normal yellow stuff pads or the yellow stuff 'R' compound?

 

[Matt82]

is there definately two compounds? i was only aware of there being one sort of yellow

 

[Leeum]

Friend of mine is under the impression there are two. He's very impressed with his 'R' compound jobbies - streets ahead of M1144's apparently.