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Discussion Starter #1
When I press the brakes I have to press the pedal hard to make the car stop even at low speed in traffic and such like. The fluid appears to be at the right level and the pads are ok although on the front there is usually a residue about 1cm from the edge on both discs. I know that the discs are from a Q4 but I wondered if was possible for the pads may be for a 2.0 16v which I have.

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Discussion Starter #2
Have you done any heavy breaking and glazed the pads.
It may be worth your while just removing them for inspection :eek:
 
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Discussion Starter #3
Will do that but don't all 155 owners brake heavily??


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Mine is like this and I think they are fairly new, going for ferodos next and some good discs, also silicon brake fluid should help(much higher boiling point) I was getting quite scared on the track while breaking and trying to dodge motorcycles! :rolleyes:
Pedal felt like a rock after! :mad:
 
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Discussion Starter #5
It's always worth removing the pads and running a file or sanding the surface to remove the glaze.
And while you're at it clean the discs with some meths.
 
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Discussion Starter #6
Oh yes i forgot that also check the caliper moves out freeley and the dust shield is in tack.
How old are the discs do they suffer from any cracking ?
Is this in reverse or going forward :eek: :lol: :lol:
Dose the car dive at the front when breaking thus rear not working and sus compensator valve/spring on the rear axle
 

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alfajack said:
Mine is like this and I think they are fairly new, going for ferodos next and some good discs, also silicon brake fluid should help(much higher boiling point) QUOTE] Is that dot 5? I've heard some scary stories about mixing dot 4 and dot 5 on road cars :eek:
 

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Run the car down hill and then switch the ignition off before trying the brakes. If there's hardly any difference in the braking force you need to apply then the Servo is probably knackered.

If the Servo is okay then either the calipers are seized, the brakellines have a blockage or the pads are Formula-1 specification and only work when really hot.

Ralf S.
 

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Not sure what it is to be truthful, I wouldnt mix though, 1 or the other, think they are quite different things,

Il go check what dot it is now :D
 
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Discussion Starter #11
Marcus I think the front discs are the same on the Q4, V6 and 2.0litre 16v.
I would check the brake bias spring. I had awful bother with the Silverstones brakes with fading, even with Red Dots and Brembo grooved discs on the front.
Basically if the rears aren't taking some of the strain, the fronts overheat very quickly indeed.
 
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Discussion Starter #12
Ralf S. said:
Run the car down hill and then switch the ignition off before trying the brakes. If there's hardly any difference in the braking force you need to apply then the Servo is probably knackered.

Ralf S.
:eek: You are joking I hope....mad advice!

Marcus, switch off the ignition WHEN AT STANDSTILL, with your foot hard on the brake pedal, you should feel the pedal sinking...thats ok :D

I think the main problem here is this 1/2" residue at the edge you're talking about..do you mean a 1/2" area hwere the pads are not contacting with the discs...this would mean you're not getting the full friction surface contact affecting braking potential of the pads...it makes a real difference!

Other possibilities....the brakes need bleeding or...when was the fluid last changed? Needs to be done every two years.

btw Jack...agree with "mave"....I've heard some bad stories about the silicon DOT5...especially after putting it into a car previously filled with DOT 4 or 5.1 You need to remove all the previous fluid and then the silicon can still find leaks previously not seen...or so I've read :D

wrinx
 

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wrinx said:
btw Jack...agree with "mave"....I've heard some bad stories about the silicon DOT5...especially after putting it into a car previously filled with DOT 4 or 5.1 You need to remove all the previous fluid and then the silicon can still find leaks previously not seen...or so I've read :D

wrinx
err, may re-consider then, havent got the equipment to pump the system out, worked ok on me dads spiders but its over 20 years older and maybe less prone to this type to problem! :rolleyes: :eek:
 
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Discussion Starter #14
You'd be better using Dot5.1.
Marcus, after re-reading, I agree with Wrinx about the discs and pads.
1cm is a BIG area to lose. Have the discs worn down and left a big ridge ???
One thing to do is "overhaul" the brakes. Just do all four wheels, remove the calipers, push the pistons back, make sure the sliding pins are all moving freely (use white grease for the pins, not copper grease). After you do each wheel, pump the brakes until the slack is taken up again, then do the next caliper. Should take less than an hour to do.

I just did this with the V6 and the brakes became excellent. I even had to slacken off the handbrake cable afterwards, which I found strange :confused:
 

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Well done Wrinx- you've just saved his life :cool:
 

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wrinx said:
:eek: You are joking I hope....mad advice!

Marcus, switch off the ignition WHEN AT STANDSTILL, with your foot hard on the brake pedal, you should feel the pedal sinking...thats ok :D

wrinx
Sorry to correct yer :rolleyes: but to check the servo is working you pump the pedal a few times to deplete the air or untill it goes hard then start the engine with your foot still on the pedal and it should sink slighlty as it builds up vacuum :D
 
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Discussion Starter #17
Damn, I nearly put I might have got it the wrong way around :rolleyes:

wrinx
 
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Discussion Starter #18
just a thought... with having such a large 'run off/residue' from the edge of the pad and the edge of the disc.. is it the pad making full contact.. if it is, is it the right size pads in there?

j
 
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Discussion Starter #19
Good Lord all this help I will try all the correct suggestion and let you know also will take a photo and put it on here for you all to see.


Thanks

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wrinx said:
:eek: You are joking I hope....mad advice!
Still crazy after all these years!! Hahahahahahaha! :lol: :lol: :lol:


Anyway, DOT5... it's a silicone-based fluid that's less prone to absorbing moisture from the atmosphere, so it gives more consistent results in operation.

The trade-off is that it is not "oily" like DOT 3 or 4.

Some brake systems (master cylinders) have seals that require lubrication.. adding DOT5 to these is like running unleaded when you have soft valve seats - the seals lose their lubrication and so eventually tear.. leading to leaks.

DOT5 is largely insert, so should mix okay with other fluids but if you're going to use it, best to drain out the old stuff first. There's no need to dismantle your brakes, just top it up with DOT5 and pump the brakes until the new flkuid comes out.. most of the old stuff will be gone then.

I'd be more wary of mixing DOT3 and 4. I just don't know what the difference is there but I presume it's reasonably significant.

Newer brake systems should be able to deal with DOT5 as the seals and o-rings they use are more durable than the older ones that need lubing. DOT5.1 is more oily though, I think so maybe a better bet for extended use.

Ralf S.
 
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