brakes feeling spongey, even after bleeding

[richard cash]

I bled the brakes today hoping that it would be this that is creating the spongy effect but it hasnt sorted the problem.

When the brake is pressed there is a lot of travel before anything happens, then is i release the pedal and apply it gets stiffer, do this 3 times and its nice and responsive but then after 5secs its back to normal.

I noticed when i was bleeding them that the pads on the front didnt have much left on them, but they arent down to metal or anything like that.

Anyone know what this could be

many thanks

rich

[banned advertiser]

Could be worth checking the hoses if old, they could be giving with age, or maybe its the servo, dont they have a diaphram? and also they have one way valves.

[NixRX7]

Sometimes this can be caused by the ABS unit sticking (for want of a better word) if its sat idle for quite a while (not been called into use by severe breaking/wheels locking up)

If you have checked everyhting else such as pads/brake lines/leaks etc then you could try this

My brake pedal was exactly the same as yours, did a bit of asking / searching the net and the answer was to find a stretch of private road and then try to lock your brakes up i.e brake as hard as you can, this will cause your ABS unit to activate and may well sort your problem.

It worked for me anyway

Nick

[royal]

answer was to find a stretch of private road and then try to lock your brakes up i.e brake as hard as you can, this will cause your ABS unit to activate and may well sort your problem.

Nick

Sounds like a good excuse to me.........:Viking

[rx7veilside]

change the master cylinder for a new one..dont bother with second hand as i changed mine and the 2nd one was duff as well

[clive]

I bled the brakes today hoping that it would be this that is creating the spongy effect but it hasnt sorted the problem.

When the brake is pressed there is a lot of travel before anything happens, then is i release the pedal and apply it gets stiffer, do this 3 times and its nice and responsive but then after 5secs its back to normal.

I noticed when i was bleeding them that the pads on the front didnt have much left on them, but they arent down to metal or anything like that.

Anyone know what this could be

many thanks

rich

Hi Richard,

This could be a little bit of air still floating around but it really sounds like where the pads are low on the first application you are pumping the pistons and the pads out onto the disc\'s and that\'s where the extra travel is coming from especially if with one pump the pedal comes up quite a lot.



Stick new pads in and I recon you should O/K

[Martiny]

How about:
Wheel bearings with too much play.
Warped disc/s (even slightly)

[Jonathan_F]

How about:
Wheel bearings with too much play.
Warped disc/s (even slightly)

I\'ve got both these.

(wallet empties)

[nikp]

Or old brake fluid - with time brake fluid will absorb water and become spongy. Brake fluid is only meant to be kept in the system for something like 2 years and then replaced.

[alban1973]

I would replace the pads anyway, but the symtoms you describe are very common.  and a pain as it always happens when you arre in a hurry... If you have not undone any unions or pipes,  and you did not let air get in at the master cylinder by letting it get too low on fluid as you bleed the system.  If you only opened the bleed nipples and bleed correctly, which if you are doing the peddle:Nono!  method. the procedure is as follows. 2 people are best, start at the brake caliper which is furthest away from the master cylinder, n/s/r open the nipple press peddle down close nipple (as to to draw air in) peddle off, continue like that a couple of times, then to the other rear, keep checking the fliud level every time as well, then the o/s/f and last drivers side front.  as long as you have done that you should not have air in.........   The pain is.  as the master cylinder gets old the seals get hard, and the unused part of the cylinder bore gets slight corroision on it.  when you bleed the brake using that method you push the old hard seal into the unused corroded part of the bore which then damages the seal, then when you press your peddle fluid will then slowly get past the damaged seal. hence your pedal will slowly go to the floor. if you pump 2 or 3 times the peddal will go hard again because you have caused enough pressure to expand the seal enough to seal . leave it a few seconds and the same will happen.  i would check everything as above but if you have done it all the correct way then it is new master cylinder time...

[richard cash]

cheers alban for the info but i dont understand your description of the seals im afraid.

I have now replaced the pads but the problem hasnt been sorted. Also,when i was replacing the pads the spring clip that should be there was worn so much that it has broken in 2 (previous person put the clip back the wrong way round and it was rubbing on the disc)

when i did bleed the system i let it go below the min level so could i have air still trapped in the system?

[royal]

If you emptied the reservoir out and then filled it up you could have sucked air in.

[alban1973]

I have just found your other threads, it sounds like you had a dodgy pedal before you bled the brakes.  I would take a good guess that it would be a master cylinder prob.  to get air in from the fluid reservoir you would have to run the fluid right to the bottom untill you could not see any in the bottom, if it was just to MIn it would be fine.. If you have done this then bleed the system again and you will have to bleed it for a while to get any air out and keep it topped up while doing this. if you do it how i described then you will eventually get any air out. I still have a feeling it will be a master cylinder prob tho ...I can get parts at fairly reasonable prices (trade)so if you end up needing one I can get you a quote if necessary and send it on to you..

[banned advertiser]

Hi Richard
You could buy a kit and refurb them or you can get new from Mazda.
http://www.rotaryart.uk.com/acatalog/New_3rd_gen_engine_perf_tuning.html

[alban1973]

I would stongly advise against a refurb kit, by the time you have got new seals and then found that the cylinder bore is pitted due to age ,the new seals will work for a few weeks and then the same problem will arrise. unless you can re hone and measure correctly for the correct size seals in the old unit it is much better in the long run to but a quality,  exchange unit with a warranty, this is the only item ableing you to stop the car so dont mess about...  but check the whole system out as described before spending ££££\'s