Changed discs and pads now pedal goes to floor..

[bod1065]

Changed my discs and pads on my corolla t sport now pedal goes nearly to floor.......I never undid any bleeders or anything except taking cap of brake fluid bottle...any body any ideas....

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[marty_c83]

It will do until the pistons are back out, it's not uncommon to have no pedal at all for several pumps, and for the brakes to feel crap until they are bedded in.

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[bod1065]

I know, without the engine on the pedal is solid, soon as the engine is started and the servo kicks in,the pedal goes soft and nearly to the floor..it hardly pressurizes....the brakes work but loads of travel on the pedal shouldn't be like that with new pads and discs....

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[marty_c83]

I'm not familiar with the Corolla but have you missed any shims or anything like that? A the fluid level ok? I had a similar problem once where I had to leave it overnight as the fluid had became aerated despite bleeding, next day perfectly fine. Admittedly that was on a motorbike after a calliper change though.

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[SanaYusuf]

When I changed my discs and pads on my T-sport I had to pump the brake pedal quite a lot and as said until bedded in were a bit crap.

[oldcodger]

Sounds an odd one if you have not got any air into the fluid lines.

A bit of web searching does come up with a similar senario, seems a pad was not located properly and the first pedal pushes bent the pad brackets.

Would suggest you go back and check all the pads, sliders are free to move and not damaged.

( given the new ones are the correct pads and discs and the hub to disc surfaces were clean and the discs not showing any signs of bad run out ?)

From the driving  you have done (?)  do all four discs feel like they are working evenly , no bad pulling to the side etc ?

Also some pads come with a low pad "squeal pin" which can be fitted to the wrong side of the caliper and cause a jam ( as I found out on my smaller 1.6 recently)

If everything is free to move, then think doing a full brake bleed might be in order; its the first and easiest thing to eliminate if you still have the problem.

[bod1065]

Thank for replies guys, gonna bleed brakes this morning and check everything over, weird one it is....will let u know later how we go.....😀😀😀

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[bod1065]

Well bled brakes and still same no joy....either electrical or servo knackered.....Mmmmm gonna phone garage tommorow me thinks........!Removed! brakes....

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[SanaYusuf]

Is the car drivable then? How did you push the piston back into the caliper? And did you use any kind of grease on the piston?

[oldcodger]

Did you whip out your pads and sliders to check they were ok and free, not always obvious  somethings wrong when assembled.

Do not think it would cause your pedal problem as such, and not sure what they are like on a 1.8, but you have to fit the slider pins in the correct location, eg one pin is solid, one has a rubber on it.

If you have driven / braked for a little while, examining the pad faces may show some signs of uneven wear  if that caliper has a problem.

 

Also to follow on Yusufs point about how you pushed the pistons back, never had the problem, but seems if done aggressively, the back pressure can flip the master cylinder seals, though  have not read what the exact symptoms of that are.

Ideally, you should clamp the rubber hose and slacken the bleed nipple to release the fluid as you push the piston back. 

Even with a failed servo the brakes should still work ok, just very heavy, but with a normal pedal height, there is a continuous rod from the brake pedal  though the servo to the master cylinder.

[bod1065]

I couldn't remove the top slider bolt pin on either side as we're rounded of (previous owner)...but the bottom ones both sides were fine, so removed that bolt and the piston moved up and slid of and away from the pad carrier. Then removed carrier and pads ,cleaned up carrier , put back with new pads, I greased up the slider pins,pushed the piston back with a wooden handle, took some pushing back but they went , then put the brake piston back on and bolted back up....brakes are solid when engine is of, soon as you start up pedal goes slowly to the floor....there is a little bit of braking to stop the car but not much.....am thinking servo as brake pedals solid till engine comes on....

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[bod1065]

Phoned garage reckon could've pushed seals back in master cylinder when pushed pistons back....heard of this before but not very often.....I've changed pads and discs loads of times and never had this before,so will see......and yes I took top of brake fluid reservoir before pushing pistons back.... car going in Wednesday morning so will put up wot it is soon as I find out.....but thanx for help from everyone.....

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[yossarian247]

On ‎18‎/‎04‎/‎2016 at 9:51 AM, bod1065 said:

Phoned garage reckon could've pushed seals back in master cylinder when pushed pistons back....heard of this before but not very often.....I've changed pads and discs loads of times and never had this before,so will see......and yes I took top of brake fluid reservoir before pushing pistons back.... car going in Wednesday morning so will put up wot it is soon as I find out.....but thanx for help from everyone.....

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  That used to be quite a problem with certain Vauxhalls a few years ago but I can't say I've heard of it happening on a Toyota before.

[mickburkesnr]

I had this happen when I was changing the brakes of a Honda CR-V. Air got in to the system, and the guy I brought the car to just bled the brakes.

When you changed the brakes did you open the brake fluid reservoir? In ABS systems you're not supposed to open it so that it remains sealed. That's what I was told anyway.

[TomdeGuerre]

6 hours ago, mickburkesnr said:

I had this happen when I was changing the brakes of a Honda CR-V. Air got in to the system, and the guy I brought the car to just bled the brakes.

When you changed the brakes did you open the brake fluid reservoir? In ABS systems you're not supposed to open it so that it remains sealed. That's what I was told anyway.

I've never heard of that before. When the ABS is idle the solenoid and the pintle valves are closed which completely isolates it from the main braking system. The ABS still remains plumbed into the braking system of course and it remains primed with fluid, ready for action whenever it is activated.  

I fail to see how removing the brake fluid reservoir cap to facilitate returning the caliper pistons would negatively affect ABS performance.

 

[mickburkesnr]

13 hours ago, TomdeGuerre said:

I've never heard of that before. When the ABS is idle the solenoid and the pintle valves are closed which completely isolates it from the main braking system. The ABS still remains plumbed into the braking system of course and it remains primed with fluid, ready for action whenever it is activated.  

I fail to see how removing the brake fluid reservoir cap to facilitate returning the caliper pistons would negatively affect ABS performance.

 

I'm not sure, I only ever did it once on that car and it caused me a whole load of issues.

[bod1065]

Right car been into garage and they say there's nothing wrong with brakes....there solid with engine of, but with engine on and brakes applied and held on in stationary traffic the brake pedal should slowly go down so far as this is the pressure relief valve working so,s taking pressure from valves so not causing them to over work,apparently most Toyota's BMW's vws do this......news to me but this is my first Toyota !!!@ they say they've taken the car out and brakes are excellent stopping car no problems.....even put it on mot rollers and passed with braking force easy.......anybody else's t sport do this with the brake pedal.....

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[oldcodger]

7 hours ago, bod1065 said:

 with engine on and brakes applied and held on in stationary traffic the brake pedal should slowly go down

If you had said that initially, then I would have said yes, that does happen, seems more noticeable on some cars than others, though your original post did not really sound like you were holding the pedal on the brakes, it sounded more like when you pressed the pedal with the engine on it went to the floor almost straight away when you braked.

However, had not read about exactly why it happens like that, but as your garage has said " as this is the pressure relief valve working "  then that seems a plausible explanation, though I wonder it they really mean the servos vacuum check valve, as I do not know where a pressure relief valve is ?

You might want to watch this and similar vids about checking the servo operation

See this one, partic at 3 mins  in   https://www.youtube.com/watch?v=NSbdVdmPu0c

 

 

[bod1065]

Nice one matey yep that's wot mines doin.....never known a car do this before.....thank for the bid....because I never knew of this I instantly thought brakes no good....u live and learn....👍👍

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