Brakes dont work after changing discs and pads!

[MR.172 Cup]

I changed my front pads and discs on my 172 cup this morning! after doing both sides, i went up and down my road pumping them but my front brakes didnt work. the car is using the back brakes to stop :S.

I took off the wheel, undone the two bolts at the back of the wheel hub and the caliper came off then took off the screws from the top and bottom of the caliper. took the caliper off into two parts (the part with the brake hose stayed attached) and took out the brake pads, swapped them with the new Brembo pads and used a g clamp to slowly compact the brake back in place for the rest of the caliper to fit back into place.

Then moved onto the discs, eventually took the two screws out (they were a b!tch to take out as they had rounded off) swapped the discs and put the new screws in.

once both had been done i put the calipers back on with the new pads. put all the screws back on etc etc put the wheels back on. Then before turning the car on i pumped the brakes... then went up and down my road stopping to see what the brakes were like. BUT the front ones didnt work!!!

so i told the old man to drive and brake and it was evident that only the back brakes are working! when i was driving it i could feel the back sliding out a little on braking. before i changed them this wasnt happening? anyone know as to why this is happening?

 

[PP200t]

I can't think what you have done wrong, as I've done mine and they work. It might be worth taking it apart, and pumping the brakes without the pads, then push the piston back in. Try that a few times in case its seized? Only one side at a time.
I was also under the impression you need the car ignition on before you pump the brakes? Not sure why tho...

 

[James105]

Any strange noises being made? (I doubt it...but seen it before....pads in the wrong way round. Yes...friction material facing away from disc)
Pull a wheel off and see if the piston in the callipers have moved back out at all?

 

[.Stevo.C.]

Did you take the cap off the brake reservoir before you pushed the piston back?

 

[MartinR]

Check that you don't have too much brake fluid in the reservoir! due to winding the piston back new pads are thicker so less piston travel needed hence too much fluid.

I may be wrong but i think too much fluid and not enough air space on top affects the vacuum side of things!!

 

[Stefan.]

bleed the brakes?

 

[MR.172 Cup]

Did you take the cap off the brake reservoir before you pushed the piston back?

No, i didnt? should i do this now?

 

[James105]

No, i didnt? should i do this now?

Go see where the level is. As above get the cap off and check the level. If the piston hasn't moved back out the callipers then the level will still drop a bit once the piston has moved.

 

[MR.172 Cup]

should i turn the ignition on while the brake resevoir cap is off? then pump the brakes?

 

[James105]

Can be done with the ignition off. Engine running just provides the vacuum for servo assistance.

Rest the cap on the top though, as when pumping it can cause the fluid to "blob" up, so will stop it going everywhere should it do it

 

[rich-6]

Did you clean the disks before fitting?

 

[markkram]

Did you clean the disks before fitting?

^^^^^^^This^^^^^^^^^

Did you clean the protective coat of oil off the disks before you put them on.

 

[James105]

Did you clean the disks before fitting?

Very true indeed!!

(Although you would normally see some degree of braking, just very very poor braking. Could well be though!)

 

[Jay Payne]

Twisted the flexi hoses?

 

[obcuz]

Disks and pads should be 'squeeky' clean - had this same problem after a disk change - only a half-hearted attempt at cleaaning the disks after fitting and result - no front brakes, took them off and cleaned with meths and lightly resurfaced the pads to get rid of any contamination and all was well - suprising just how much difference it makes.

 

[MR.172 Cup]

^^^^^^^This^^^^^^^^^

Did you clean the protective coat of oil off the disks before you put them on.

Hmm i think this may be the problem.. i put on the new brembo Max discs. Didnt clean them or anything, just out the box and onto the car?
Ive driven it abit more and it feels alright now but it should feel alot sharper as the pads are thicker (because they are still new?)

 

[Djw John]

Ah yeah that'll be the issue then, you always need to clean the oil off, you can buy cans of brake cleaner for a few quid.

 

[Jonny1*2]

I've changed lots of discs now and never needed to clean them before use. Unless you have managed to get grease on the contact surfaces?

 

[DannyR]

I imagine they just need bedding in

 

[Tony Hunter]

Scary really, isn't it.

 

[DannyR]

Little bit...

 

[Owen92]

Most disks come with a protective layer of oil to stop them corroding before being fitted. This oil will be stopping the front brakes from providing the friction required to slow the car. Take them off and clean the disks and clean the pads. And when pushing the calliper back you should always take the brake fluid reservoir cap off to prevent blowing seals

 

[DannyR]

That oil comes off very quickly.

They need bedding in, that is all.

 

[TheEvilGiraffe]

Take it all off. Clean the discs. Pray to Batman that you've not ruined the pads already. Ask an adult to help you bleed the brakes.

Then come back to us...

Scary really, isn't it.

:dead:

 

[MR.172 Cup]

i think its sorted now guys! just needed bedding in. I didnt open the brake fluid reservoir, however when i done that and pumped the brakes, closed it up and went on a drive, all seemed fine. thanks very much for your help

 

[James105]

Glad you got it sorted! No brakes isn't a pleasant experience!haha

 

[MR.172 Cup]

Glad you got it sorted! No brakes isn't a pleasant experience!haha

The rear brakes were working but the front ones were non existent! good to know what not to do next time!

 

[DannyR]

Would just like to point out nobody said that until me nearly 20 posts in! LOL!

 

[MR.172 Cup]

Would just like to point out nobody said that until me nearly 20 posts in! LOL!

"I changed my front pads and discs on my 172 cup this morning! after doing both sides, i went up and down my road pumping them but my front brakes didnt work. the car is using the back brakes to stop"

Lol

 

[James105]

Would just like to point out nobody said that until me nearly 20 posts in! LOL!

Have a gold star!haha!
Least it's all sorted