MK5 Golf GTI
All Things Mk5 => How to Guides / Troubleshooting => Topic started by: GTICZ on November 10, 2017, 11:54:04 am
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Hi guys,
have problems with brakes, but there is no fault code in vcds, no dashboard lights or any other clue..
When i start my car mkv gti 06, few of first braking are not much strong, i thinking about very weak brake power, after while and kick to the brake pedal its getting better, but almost in every trying to stop, some rattle ( ABS? ) in pedal is on, but still no lights on dash.. the car is quite stopping performance at these situation, but sometimes when i really need full brake performance, hit the pedal and immediately pedal push agains my foot, same rattle noise and then there is weak brake power, so its hazard and better jump out of this car would be safer :driver:.. nobody knows what should causing this, maybe because when i showed it to mechanics, my car started to brake like never before....
does anyone knows, what should i check please?
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Tyres? Sticking calipers?
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i have michelin ps4 in front with 6mm, due to ive broke previous dunlop sport maxx rt, which i have in rear about 5mm.. no signs of sticking caliper
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Sounds like the ABS is kicking in more than it should. Multiple causes, easiest way to find out is get it on VCDS and log the wheel speed of each wheel and see which sensor is giving you a duff reading and causing the ABS to kick in, then investigate further......
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Yeah VCDS to the rescue. I mentioned tyres because mine (also PS4) are down to 3mm and the ABS kicks in quite often on damp roads. There's just no grip on semi bald tyres this time of year.
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on vcds all of wheels are the same..
but to Pudding: ive just changed summer to winter tyres and when i tried push brake pedal harder, right rear wheel was locking and then abs kicks, another thing is, pads on this particularly wheel are almost gone, so probably you were right with sticking caliper... now i have to find out why... i already change it cause last winter i noticed this wheel is warmer then otherside, but with new caliper was it the same.. so i returned back and otherside has play in caliper, so i bought new one on left and from this time, never look at right side :slap: but, my friend from workshop told me, that new trw are crap because they are just rebuild and very problematic...so maybe, caliper on right side which ive tried change could have been damage also.. due to this possibility, i did not think about bad caliper..
right rear wheel on jackstand is freely moving with no sticking.. so i dont know, if still could be caliper, or for example master cylinder or abs unit itself?
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Crap / old / incorrect specification brake fluid can cause ABS activation problems. The best brake fluid by far is the OEM VW brake fluid (in the cylindrical tin can).
Another crucial point to note is that when doing your annual (yes, I did mean yearly) brake fluid change, you MUST repeatedly cycle the ABS/ESP unit through its test procedure with VCDS or VAS. The Conti/Teves units fitted are extremely susceptible to going expensively wrong if used with old fluid.
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Another crucial point to note is that when doing your annual (yes, I did mean yearly) brake fluid change, you MUST repeatedly cycle the ABS/ESP unit through its test procedure with VCDS or VAS. The Conti/Teves units fitted are extremely susceptible to going expensively wrong if used with old fluid.
in output tests? do you know, if there is selective or sequential, so i have to go throw all procedure?
should i have pressure bleeder connect while do the procedure, or just check fluid level?
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The VCDS test on the ABS is where you have to hold the brake pedal down hard, click on the 'next' button, and the brake pedal grinds away like a jack hammer. You MUST have a fully charged battery, in top condition - otherwise keep the engine running, as two complete VCDS cycles can flatten the battery!
My preferred order (get yourself a box of 6 one litre cans of genuine VW brake fluid.)
1. Pressure bleed front left, front right, rear left, rear right - until clean fluid appears. It is also good to manually press the brake pedal hard to the floor BRIEFLY two or three times whilst pressure bleeding each nipple
2. Cycle the VCDS procedure (twice if never done before).
3. Repeat number 1 (pressure bleed only, leave the foot pedal) - but wait until you get a cloud of black contaminated fluid to pass through each nipple, and wait until clear. Try to remember how long it takes for the crap to arrive at each nipple
4. Repeat number 2 again (one full cycle on VCDS).
5. Repeat number 3, and hope no more crap appears!
Then change your brake fluid every year, but start with the VCDS cycle before pressure bleeding.
As for the rear calipers, it is well known that the TRW supplied ones are pants - not just on VWs, on any other marques they are fitted on. If you are competent, ideally get a pair of spares, and strip them down yourself and refurb them. Get a good quality magnifying glass to check the smoothness of the piston bores. I have seen many supposedly 'factory reconditioned' TRW calipers with scores on their bores!
HTH
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TT: thank you. when vcds cycle, should i have bleed nipple open or just run cycle and than bleed again?
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Crap / old / incorrect specification brake fluid can cause ABS activation problems. The best brake fluid by far is the OEM VW brake fluid (in the cylindrical tin can).
Another crucial point to note is that when doing your annual (yes, I did mean yearly) brake fluid change, you MUST repeatedly cycle the ABS/ESP unit through its test procedure with VCDS or VAS. The Conti/Teves units fitted are extremely susceptible to going expensively wrong if used with old fluid.
The Conti/Teves units fitted are extremely susceptible to going expensively wrong if used with old fluid.
what goes wrong with the ABS units if old Fluid ?