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Model specific boards => Golf mk3 => Topic started by: WeekendMechanic on 20 February 2015, 19:17

Title: Weak brake servo
Post by: WeekendMechanic on 20 February 2015, 19:17
So iv bleed the brakes and I swear if someone tells me to bleed again I will shoot them, so the pedal is hard and firm but when I brake especially at high speeds I have no to little assistance .
I have no leaks what so ever can someone please give me the go ahead to change the servo?and please don't tell me to bleed the brakes again I swear.....
Title: Re: Weak brake servo
Post by: VW BUSH on 21 February 2015, 00:48
Sure you have enough vacuum at the servo?
Title: Re: Weak brake servo
Post by: gasketface on 21 February 2015, 01:02
Why did you have to bleed the brakes in the first place ?.Have you had the system apart for some reason or was it just because they were a bit spongy ?.Have you changed the front pads and if so what make/type did you fit.

Sorry for all the questions but if your car idle's o.k. and engine runs smooth and there are no obvious air leaks then maybe it is'nt the servo.Just trying to save you the job of changing it coz it's a pain to do !.

Is this car new to you ?.What were the brakes like before you did whatever it was (if anything) that required the bleed ?.More info needed ????.

Iv'e never had a problem with a servo on a Golf so i'm not sure if this applies to a one but on another car i had years ago i had a similar problem and it turned out to be the one way valve on the pipe that goes from the inlet manifold to the servo.It was'nt working one way,it was leaking and allowing the vacuum to return to the inlet.I don't even know if a Golf has a one way in that pipe but i suspect it has.
Title: Re: Weak brake servo
Post by: WeekendMechanic on 21 February 2015, 06:53
The cars brakes have been like this ever since I got it 2 and a  1/2 years ago front and rear pads and shoes are genuine from the dealer,
No golfs don't have a the vacuum line connected to the inlet instead it comes from a vacuum pump with a one way valve but that is fine,yesterday I connected a high vacuum vacuum pump directly to the servo and it worked a little better but not a whole lot I have driven old skodas and fiesta were the brakes are beautiful Iv never had perfect brakes on my golf but I doubt they were like this from stock.
Title: Re: Weak brake servo
Post by: VW BUSH on 21 February 2015, 13:14
The cars brakes have been like this ever since I got it 2 and a  1/2 years ago front and rear pads and shoes are genuine from the dealer,
No golfs don't have a the vacuum line connected to the inlet instead it comes from a vacuum pump with a one way valve but that is fine,yesterday I connected a high vacuum vacuum pump directly to the servo and it worked a little better but not a whole lot I have driven old skodas and fiesta were the brakes are beautiful Iv never had perfect brakes on my golf but I doubt they were like this from stock.
Ahh you have a Diesel....Petrol golfs use vac from the inlet.
If it got better when you put extra vac on it that might be a clue.
Title: Re: Weak brake servo
Post by: WeekendMechanic on 21 February 2015, 15:21

[/quote]
Ahh you have a Diesel....Petrol golfs use vac from the inlet.
If it got better when you put extra vac on it that might be a clue.
[/quote]
Yes diesel and iv read through horror stories when this happens a guy on there replaced almost every brake system part took it to experts and still Could not get the right pedal.Im being to think after a master cylinder change and numerous bleeds I got one of those lemons
Title: Re: Weak brake servo
Post by: spikenipple on 21 February 2015, 16:32
Sounds like it might be the servo itself if everything you've checked so far hasn't found the problem.
Title: Re: Weak brake servo
Post by: itavaltalainen on 22 February 2015, 02:15
Does the brake get better if you step on it quickly?

I had similar symptoms and it was master cylinder (internal seal started to perish). Seal worked at higher brake pressure.
Title: Re: Weak brake servo
Post by: WeekendMechanic on 22 February 2015, 05:00
Does the brake get better if you step on it quickly?

I had similar symptoms and it was master cylinder (internal seal started to perish). Seal worked at higher brake pressure.
Yes this is sort of what is happening when the car is running and I apply firm pressure the pedal slowly sinks to the floor if I release and brake after that the brakes work well for a minute ,the new master cylinder I bought was a cheapo under 30 euros I will buy a new ate one and see what happens.
Title: Re: Weak brake servo
Post by: WeekendMechanic on 22 February 2015, 12:08
Can I ask a question is the brake pedal supost to slowly sink to the floor with firm pressure on it?Can someone please check for me please. 
Title: Re: Weak brake servo
Post by: LR5V on 22 February 2015, 16:48
If the pedal slowly sinks to the floor, it is failed master cylinder seal -so new master cylinder required.
Title: Re: Weak brake servo
Post by: VW BUSH on 23 February 2015, 14:46
If the pedal slowly sinks to the floor, it is failed master cylinder seal -so new master cylinder required.
there you go
Title: Re: Weak brake servo
Post by: WeekendMechanic on 23 February 2015, 19:57
I know but would a cheap master cylinder that I installed do the same thing is it just a coincidence?
Title: Re: Weak brake servo
Post by: WeekendMechanic on 25 February 2015, 13:44
It's weird because I adjusted the handbrake cable's made it firm and the pedal feels a little firmer,brakes lock like I want to now when I press down I'm not 100 percent happy maybe 60 percent compared to other car brakes iv driven but the only other option is to shoot myself in the head or spend tones of cash replacing parts so I m going to opt for the other option and just be depressed.
Title: Re: Weak brake servo
Post by: madmatty on 02 March 2015, 14:25
if the pedal feels harder after the cables are adjusted then it sounds like the drums are not adjusted up correctly.
ive done loads of derv conversions on t3's using mk3 engines and had a few with bad vac pumps take the vac line of and see how much is produced have had a few with cracks around the plastic outlet from the pump that does just what your discribing
Title: Re: Weak brake servo
Post by: WeekendMechanic on 05 March 2015, 15:36
Thanks for all your suggestions but i`m just going to leave them the way they are