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Discussion Starter · #1 ·
I have just changed the rear brake disc on my Megane and the brake pads will not retract. They are tight on the caliper. I managed to remove the caliper and refit to the new disc with a little persuasion and thought that a few brake operations would release the pads but they are still hard on the disc. The car will move but not drive without friction on the disc.
How can I back off the pads?
 

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Hi

never thought about that, I just turn them the direction that makes them go in !

Al
 

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Technical Supremo, Platinum Member
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From memory I think they’re right hand threaded to wind in, test by winding one in a small amount with pointed nose pliers.
To be honest if they aren’t stuck the pliers will do the job without needing a tool to do it.
 

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Hi

don't forget you're supposed to open the bleed valve when retracting the pistons, don't just force them in can cause ABS or m/cyl issues if you do .

Al
 

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Re: Megane - reasr brake disc change

Uh oh. Too late to open the bleed valve now... Lets hope nothing bad happened. Clockwise to go in yes - bought the tool but i realized it was quite unnecessary yes.

I managed to change all 4 brake discs and pads. Was a bit fiddly to make everything moove smooth again because of the rust build up on the calipers pinching the pads on two wheels.( Old ones were pretty siezed.)Wire wheel and copper paste to the rescue.

However it seems my right rear brake is grabbing a little bit when i spin the wheel. It's not hard to spin but i can hear the disc and pads slightly touching and the wheel does not spin completely freely. Is that normal? The caliper pins move fine and the pads are not stuck. Can it be the piston that is siezing a little bit and not retracting far enough or something like that?

Thanx for the help!
 

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Is the handbrake completely off and the lever back on the stop ?
There is some slack there and the lever looked to be on the stop. The hand brake arm seemed to move ok but I'll double check that, thanx!

Sorry for a noob question but are the pads supposed to clear the disc completely after breaking? I mean there is no return spring or force that lifts them from the disc. If they are a bit pinched by the support i guess they might be left slightly touching the disc? For the front left i had to grind away some material from the pad sliding contact points because it was too tight against the metal guiding clips and couldnt move. Perhaps i should re-check that the pads on this right rear wheel are indeed free to move but they seemed ok when installing.
 

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Can I be a little pedantic please....there's no E in braking !!! (sorry but it winds me up :frown2:)

Anyway.
Pads have nothing to retract them, it is simply nothing to push the onto the disc so any contact forces them back until clear.

If not being held on by handbrake, common is sticking slide pins or the pads sticking in the carriers.
The latter often with new pads if a little too much burr or paint.
Less common is that a flexible pipe has broken up inside and is not allowing fluid to return.
 

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Braking braking braking. (I'll try to remember that now thanx ;) English is not my native tongue as you might have noticed so feedback and corrections are always welcome. Only way to learn.)

I guess in the best case they are just a bit too new and tight to retract completely. With new discs and pads is there a "run-in" period for them to align and get along?
 

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If you look at the old pads you'll see that the surface isn't always level with the backing plate as the caliper can be slightly out of line in respect to the disc surface. When new pads are fitted unless you have fitted new discs the brake pedal feels slightly springy as the new pads are only in contact with the discs in one or two spots and need time (say 200miles) to wear down into the same undulating profile as the discs, until then the brakes are not 100%, so your old brakes were actually better with the old pads up to this point - forgetting aspects like sticking sliding pins or pistons.
 

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I see! However I changed all discs as well. So both pads and discs are brand new. I guess the caliper might still be slightly out of alignment with the disc anyway - maybe that's causing one side of the pad to slightly rub against the disc. I guess I'll see next weekend, I should have around 200-250 km on her by then. She failed the mot due to rusted brake discs and too much difference between front brake forces, and I'm going back for a re-check on friday with all my new components.
 

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If you think the new disc may be running out of true, you may have some dirt or damage on the mating faces.
Bit of a pain but remove and clean.
Also are you sure the disc is not warped (can happen even with new)
I'd also be fetching the pads back out and making sure they are free in the caliper.... lost count of the number I've had to file a little on the ends where they mount into the caliper.

Depending on how bad, brakes will fail on rolling road test if they are binding.
And may be unbalanced on brake force if it is down to pads or slide binding.
 

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Excellent info. Thank you, I think I know what to re-check now. I did try to clean the mating surfaces thoroughly but I might have missed something. The binding is really not bad but you can hear it when spinning the wheel with the car jacked up.
 
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