|
I've noticed that the footbrake has an occasional problem, usually after a burn-up. The brake pedal seems to push down with lessened effect, and keep going down - as if there's fluid bypassing the piston in the master, for example. I am not sure it is that, though, that's just to give an idea of what it feels like. A rather unfortunate feeling, as if the thing's not going to stop! Normally, it's fine, and will lock the wheels. What's up?
Last edited by: VxFan on Tue 25 May 10 at 18:51
|
That sounds exactly like brake fade to me. Don't rag it so hard? ;-)
Changing the brake fluid, or at least bleeding it, would be my advice to start off with.
|
|
Year = 19? What's the correct year please.
|
>> Year = 19? What's the correct year please.
Looks to be a bug in the site software - it cuts short the model designation supplied by the drop-down.
|
>> Looks to be a bug in the site software
No bug. User selects the model (which has the build years in brackets, but doesn't get displayed due to space reduction) then the user is required to fill in "year of manufacture" which only allows 2 digits. If you put 2003, then it will only display 20. Right next to the box is an example - "e.g. '03' for year 2003"
Last edited by: VxFan on Tue 25 May 10 at 13:52
|
>> >> Looks to be a bug in the site software
>>
>> No bug. User selects the model (which has the build years in brackets) then the
>> user is required to fill in "year of manufacture" which only allows 2 digits. If
>> you put 2003, then it will only display 20. Right next to the box is
>> an example - "e.g. '03' for year 2003"
I did a post preview with a 2 digit year and it still truncated it.
|
>> I did a post preview with a 2 digit year and it still truncated it.
I can only get it to display 2 digits for the year on preview.
|
>> That sounds exactly like brake fade to me.
Um. The pedal actually travels downwards during braking - it's not simply that the efficiency of braking is impaired.
>> Don't rag it so hard? ;-)
Spoilsport!
>> Changing the brake fluid, or at least bleeding it, would be my advice to start
>> off with.
The brakes are normally "hard", that is it does not show symptoms of having air in the system.
?
|
>>>The brakes are normally "hard", that is it does not show symptoms of having air in the system?
Ah yes but as this explains...
Most major vehicle manufacturers recommend that drivers should change their brake fluid every two years. This is because brake fluid is a hygroscopic fluid - meaning that it absorbs water over time reducing its effectiveness.
If the fluid is not changed before the water content reaches the 3% mark, the water brings down the normal boiling point of the brake fluid and air bubbles are created as a result. Once this happens, the brakes become ineffective and dangerous.
If that wasn't bad enough, a motorist probably won't even be aware that this has taken place because the braking system will appear completely normal until the brake fluid reaches the reduced boiling point - which usually occurs after braking heavily.
|
|
It's odd, though - it happens not after repeatedly braking, but upon braking having had a good burn-up. Perhaps something's binding. Perhaps it's something to do with the ALB pump. Perhaps...
|
|
do as your told, and change the brake fluid, and then if it fails come back here and start pondering.
|
When was the fluid last changed FT, that would be my first port of call too.
Whilst getting down and dirty you could give the brakes the once over making sure any self adjusters/sliders haven't seized or sticking due to winter salt, and checking the pads are all good/ and firmly bonded...daresay you've already done that though.
|
>> When was the fluid last changed FT, that would be my first port of call too.
>>
>> you could give the brakes the once over making sure any self adjusters/sliders
>> haven't seized or sticking due to winter salt, and checking the pads
I tried an experiment today. Pootling along, and applying the brakes gently. Sometimes OK, sometimes that sinking feeling (in more ways than one). Applying the brakes hard results in effective braking, with no sinking of the pedal (which then feels "solid"). It's as if fluid is sometimes leaking somewhere internally (however, there's plenty of fluid in the resevoirs) - the brakes are not spongy at all. It's a mystery. Oh, if I park, jam the brakes on, then get out and try to push, there doesn't seem to be rolling resistance. If the pads were U/S, then I don't think that would result in the peday slowly sinking when braking. Um.
|
You are almost decribing what i've seen before with master cylinders needing overhaul (''sinking feeling''), but i'd leave that alone for the time being, possibly a servo problem?
Full brake strip out if not already done, clean and check everything, coppaslip pads and any caliper sliders, grease pistons after pumping them out a little, reassemble and flush through with fresh fluid....that would be my way forward for starters.
I'm assuming you have discs all round, if you have rear drums are the slaves ok?
|
>> You are almost decribing what i've seen before with master cylinders needing overhaul (''sinking feeling''),
That's what I think, but with the car being 11 years old it would be safer and easier to buy a new master cylinder. If that cures the problem then it won't be necessary to ...........
>> Full brake strip out if not already done, clean and check everything, coppaslip pads and
>> any caliper sliders, grease pistons after pumping them out a little, reassemble ...
However, I agree with ..........
>> flush through with fresh fluid ....
|
Clamp all 4x flexi brake pipes and pump the pedal is it hard? if not look at the master cylinder undo the bolts to servo and gently prize back any fluid at front of master?
If pedal is hard remove one flexi and try pedal it may show which circuit is your problem like a leaking wheel cylinder or brake caliper.
Had a sierra that was 12yrs old and had brake fade turned out been the master cylinder new one fitted spot on, but you do need to check the braking system before replacing just the master.
|
>> Clamp all 4x flexi brake pipes and pump the pedal is it hard?
The brakes are most often quite normal. Sometimes when applying the footbrake reasonably gently it seems to just slowly travel down. The brakes work.
>> is your problem like a leaking wheel cylinder or brake caliper.
It's not leaking any fluid.
|
Hi FT,
You have been given some very sound advice about changing the fluid and as a vehicle technician for many years, this MUST be done as a priority. From the description given it is the most likley cause of your intermittent sponginess. To change the fluid is quite straightforward and cheap. Don't go looking for problems that may not be there. You are driving a vehicle which 'could' end up with brake failure - change the fluid at your earliest opportunity, then report back to us. If it's not worked then we 'the offerers of wonderous knowledge' will assist you further.
Hope this helps
Robin the Technician
|
>> with the car being 11 years old
Um. It's a 1990 model.
|
|
My brain said 20 but my fingers typed 11. D'oh!
|
as everyone has said
hondas in particular seem to be prone to boiling their brake fluids sometimes if everything isnt tickety boo,last time i had it on a honda it and it was due to sticky rear brakes boiling the fluid
do a fluid swap first and then consider a master cylinder if things dont improve
|
Honda Accord UK - 19 2.0 Brakes "fade". - Dave_
