Restoring brake pressure

BraveDonut

Changed the back brake pads on the wife's 05 megane.
It wasn't bloody easy:mad: - i needed to go to a garage and borrow a special tool to push the pistons back to get the calipers back on.
Anyway...... I lost a bit of fluid in the process, which I topped up.

There was no pressure in the brakes, so I thought that I should bleed them.

I did both sides on the back as follows:

Built some pressure by pumping the brakes and then held that pressure. Released the nipple on the brake. Fluid came out. Tightened the nipple.
Repeated on driver's side.

There is pressure in the system now but not enough.

Have I done something wrong here?

Avns1s

BraveDonut wrote: »

Changed the back brake pads on the wife's 05 megane.
It wasn't bloody easy:mad: - i needed to go to a garage and borrow a special tool to push the pistons back to get the calipers back on.
Anyway...... I lost a bit of fluid in the process, which I topped up.

There was no pressure in the brakes, so I thought that I should bleed them.

I did both sides on the back as follows:

Built some pressure by pumping the brakes and then held that pressure. Released the nipple on the brake. Fluid came out. Tightened the nipple.
Repeated on driver's side.

There is pressure in the system now but not enough.

Have I done something wrong here?

Clearly there is still air in the system so you will have to bleed again. Are you bleeding properly as it is a 2 person operation the way you are doing it.

I am just wondering why you lost fluid while changing pads? I normally just remove any build up of excess fluid from the reservoir with a syringe as I am pushing back the pistons, keeping an eye on the level as I am doing so of course. There is no need to bleed when doing it this way.

guil

Ya have to keep doing it on each caliper until the fluid stops spitting out of it. When it flows out steady with no bubbles it's done properly. Ur best bet is to get a clear plastic tube to fit over the nipple or else get a brake bleeding kit. They're only about 15 euro and make it much easier. Ya can also get one with a one way valve so ya just open the nipple and keep pumping till there's no bubbles in the tube

Just make sure ya keep an eye on the reservoir or else ur pissing against the wind

BraveDonut

I lost the fluid while trying to figure out why I couldn't push back the pistons.
Typical of Renault to make this difficult. I had to get a special tool to force back the piston while turning it.

You are correct, I was using a two-person operation to bleed. I had the wife doing the brakes.

Just bleed again? Should I do all four wheels?

Thanks for your help

bladespin

BraveDonut wrote: »

I lost the fluid while trying to figure out why I couldn't push back the pistons.
Typical of Renault to make this difficult. I had to get a special tool to force back the piston while turning it.

You are correct, I was using a two-person operation to bleed. I had the wife doing the brakes.

Just bleed again? Should I do all four wheels?

Thanks for your help

Most cars require a caliper rewinder for the rear brakes unfortunately, keep bleeding the system is the only way, the pumps are great but you can do it without one just takes patience and a helpful spouse

richardsheil

Not really typical Renault to be honest. Many cars have this combined disc brake / handbrake system.

It would have been better to understand this before you started.

However, are you sure now that you have a problem with low pressure at the rear? The car probably has a load sensing valve in the back and with an unladen car you should not expect much rear braking anyway.

Similarly the problem could be just that the pads are not bedded in yet.

Really what I am saying is, to try and be sure it needs further bleeding before doing this task.

Hope this is helpful

Avns1s

BraveDonut wrote: »

I lost the fluid while trying to figure out why I couldn't push back the pistons.
Typical of Renault to make this difficult. I had to get a special tool to force back the piston while turning it.

You are correct, I was using a two-person operation to bleed. I had the wife doing the brakes.

Just bleed again? Should I do all four wheels?

Thanks for your help

Shouldn't be any need to do the fronts assuming you didnt open the brake lines. Make sure Mrs Brave Donut keeps her foot firmly on the brake pedal even if it goes to the floor while you have the bleed nipple open.

sundodger5

make sure the wheels are on the ground when bleeding them. as mentioned above the load sensing valve will not be letting much pressure through if wheels are up.
also did you try to force caliper back before discovering the caliper wad wind back?

BraveDonut

Thanks for all the help here.

I will try to bleed again with a mate who "gets it".

Cheers all!

Captain Slow IRL

Pads take a bit of time to bed in - you will get a numb feeling and the brakes will not be as effective until they are bed in. You should be driving a little easier until you are confident about their stopping power.

If the only fluid you lost was through the filler bottle, topping it up should have been sufficient and bleeding the brakes was not necessary.

If there's no massive improvement after your friends help, try bringing it to a garage for peace of mind and to ensure everything is as it should be.

mickdw

Firstly I dont agree with pushing the fluid back through the system as Avns1s said. There is always a possibility of damaging/reversing a seal when doing this. Better IMO to just release fluid at each caliper and do a quick bleed when finished.
In the OPs case, I would do another bleed, being sure to do it properly. Then allow the pads to bed in. If your discs are in poor shape, it is possible that the pedal could be going quite near to the floor and also giving very poor braking until the pads bed into the disc surface gradually giving you back good solid pedal

BraveDonut

All done and good pressure again.
Thanks for all of the help everyone!

richardsheil

You got tons of suggestions there. Could you give some detail on which pieces of advice you took and how the repair went?