Hard brake pedal

Stu · 1 Hard brake pedal 2nd April 2015, 11:06 am

Stu

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When i put my foot on the brake pedal its solid.
Brakes work but theres hardly any travel of the brake pedal.
Whats likely to be the problem.
Would bleeding the system sort it out.
Its had new yellow stuff pads all round and one section of brake pipe changed due to corrosion.
Also has had braided brake lines.
This was all done by previous owner.
Was told that its had new fluid too.

GTI-R US · 2 Re: Hard brake pedal 2nd April 2015, 11:35 am

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assuming calipers are free on slides then it will be a seized master cylinder

Stu · 3 Re: Hard brake pedal 2nd April 2015, 11:41 am

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Yeah i took all calipers off and copper slipped them.
Does this mean i need another master cylinder Bob?

johnboy · 4 Re: Hard brake pedal 2nd April 2015, 2:31 pm

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If the brakes work fine, doesn't that mean that the master must be moving?
If seized I'd have thought brakes would be stuck on or off...

Mr B · 5 Re: Hard brake pedal 2nd April 2015, 2:40 pm

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Is your servo working !
Does the pedal feel different with engine running to engine off !
Have you visually looked at the calipers while someone operating the pedal so you can see each piston move/assembly flexing.

mikewazowski · 6 Re: Hard brake pedal 2nd April 2015, 2:59 pm

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on the subject of brakes and servos, is it normal for the revs to go up by around 100rpm when pressing or releasing the brake pedal?

Stu · 7 Re: Hard brake pedal 2nd April 2015, 3:17 pm

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Pedal feels the same with engine on or off.
The disks had surface rust on and i have driven the car up and down the road and the surface rust has gone off all of the disks.
The pedal moves about 1 inch when i press it. But like i say its hard.
The reservoir was full to the brim. So i have taken some out and its now at max..
I havent had anyone with me to check what happens when i press the brake pedal.
Will get my eldest to sit in the car tomorrow while i look.

Stu · 8 Re: Hard brake pedal 2nd April 2015, 3:27 pm

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I did notice. When i took the pads out to clean everything up and copper slip everything.
When putting the brakes back together it was very tight.
New disks and pads made the gap between piston and calipers none existent. ..
Thats with pistons pushed right back.

Mr B · 9 Re: Hard brake pedal 2nd April 2015, 4:28 pm

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My guess from your comments is servo issue/vacuum to servo or indeed master cylinder issue .

Stu · 10 Re: Hard brake pedal 2nd April 2015, 4:31 pm

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Is the servo that thing at the top of the bulkhead passenger side?

Stu · 11 Re: Hard brake pedal 2nd April 2015, 4:41 pm

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Hard brake pedal 20150402_173500_zpsoqbozlwc

Hard brake pedal 20150402_173544_zpswam9w45y

Mr B · 12 Re: Hard brake pedal 2nd April 2015, 4:43 pm

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^ no you looking at abs pump, servo is the black cylinder drum behind the master cylinder, it has a diaphragm inside which is open to engine vacuum when depressing the brake pedal & that assists you in force applied to master cylinder .... as a start you want check the servo vacuum feed & 1way valve is working/plumbed correct.

Stu · 13 Re: Hard brake pedal 2nd April 2015, 4:57 pm

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Mr B wrote: as a start you want check the servo vacuum feed & 1way valve is working/plumbed correct.

Where will i find the vacuum feed and how would i check if the 1 way valve is working?

Stu · 14 Re: Hard brake pedal 2nd April 2015, 5:06 pm

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Stu wrote:

Mr B wrote: as a start you want check the servo vacuum feed & 1way valve is working/plumbed correct.

Where will i find the vacuum feed and how would i check if the 1 way valve is working?

Hard brake pedal 2015-04-02%2018.05.22_zpsevjf4rvr

Stu · 15 Re: Hard brake pedal 2nd April 2015, 5:18 pm

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Stu wrote:

Stu wrote:

Mr B wrote: as a start you want check the servo vacuum feed & 1way valve is working/plumbed correct.

Where will i find the vacuum feed and how would i check if the 1 way valve is working?

Its conected the same as this.
But where it says conect to the large pipe on carbon canister.
Is that the one at the bottom or one of the top ones?

Thermal · 16 Re: Hard brake pedal 2nd April 2015, 5:45 pm

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Most MOT testers check the brake servo by pumping the brake pedal quick and hard 5-6 times and then hold the pressure on with the last pump, then start the engine, you should feel the pedal drop away 1/2 in or so, this indicates that your servo is working, I did MOT's for about 8 years and was the method we always used! I don't se anything different about the pulsar.

Mr B · 17 Re: Hard brake pedal 2nd April 2015, 5:53 pm

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" that initial check for basic function.
If fails that mot style check, pull vacuum line off the servo & check it getting vacuum, if not trace back check the one way valve. If you getting vacuum to servo it either servo issue or master cylinder. hard to be accurate without actually physically looking at it.

Stu · 18 Re: Hard brake pedal 2nd April 2015, 6:07 pm

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Its just rock solid. Dosnt change when i start the car up after pumping the pedal.
I took the vacuum hose off the booster at the top.
Blew down the end to the master and it was hard to blow. So sucked and it released. So guess thats a valve okay?
Blew towards the booster at back of plenum and i could blow and suck freely...

Thermal · 19 Re: Hard brake pedal 2nd April 2015, 7:22 pm

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Hmmm, as Mr B suggests check you have vacuum at the servo with the engine running, although it will run badly with the pipe disconnected, if that is Ok you could try to bleed one of the brake calipers and see if you have full travel on the pedal, that should indicate if you have a seized master cylinder.
Got a few issues with mine at the moment, so I know how frustrating it can be.

Stu · 20 Re: Hard brake pedal 2nd April 2015, 7:35 pm

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Thermal wrote:Hmmm, as Mr B suggests check you have vacuum at the servo with the engine running, although it will run badly with the pipe disconnected, if that is Ok you could try to bleed one of the brake calipers and see if you have full travel on the pedal, that should indicate if you have a seized master cylinder.
Got a few issues with mine at the moment, so I know how frustrating it can be.

Just tried that.
Started car and as i was undoing that hose i could hear hissing and then as i took the hose off the car stalled.
I will try bleeding one caliper tomorrow to see if the pedal will go down to the floor.
Thanks for all the help so far guys Smile

Mr B · 21 Re: Hard brake pedal 2nd April 2015, 7:45 pm

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Your blowing/sucking sounds wrong :-)
from hose end from servo you should be able blow down it but not suck. Is best run engine & check for strong vacuum at this pipe, block it prior to starting or wedge it back on servo then once started remove & inspect for strong vacuum.
Pretty sure the one way check valve is inside the hose if original hose & close to servo end of the hose.
Bleeding some fluid from brakes is another good test idea & results from that should eliminate or prove master cylinder, personally at moment I would be thinking Servo faulty or servo check valve faulty..

Stu · 22 Re: Hard brake pedal 2nd April 2015, 8:03 pm

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Which way should this arrow be pointing on the hose?
Hard brake pedal 20150402_210140_zpsrgzxfrkn

At the moment its pointing away from the servo. Towards the front of the car.

Thermal · 23 Re: Hard brake pedal 2nd April 2015, 8:36 pm

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That looks correct as the arrow indicates direction of flow, (I know it dosent actually flow, more direction of suck) so as long as the arrow points towards the engine it should be correct.

johnny gtir · 24 Re: Hard brake pedal 2nd April 2015, 8:38 pm

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Personally i think its over complicated whats the rear brakes like stu ?

Stu · 25 Re: Hard brake pedal 2nd April 2015, 8:45 pm

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Thermal wrote:That looks correct as the arrow indicates direction of flow, (I know it dosent actually flow, more direction of suck) so as long as the arrow points towards the engine it should be correct.

i guess its time to check the pedal drop when i try to bleed the system then.

johnny gtir wrote:Personally i think its over complicated whats the rear brakes like stu ?

How do you mean?
All brakes seam to be pulling up okay. And they have new pads and disks.

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Hard brake pedal

1 Hard brake pedal 2nd April 2015, 11:06 am

Stu

2 Re: Hard brake pedal 2nd April 2015, 11:35 am

GTI-R US

3 Re: Hard brake pedal 2nd April 2015, 11:41 am

Stu

4 Re: Hard brake pedal 2nd April 2015, 2:31 pm

johnboy

5 Re: Hard brake pedal 2nd April 2015, 2:40 pm

Mr B

6 Re: Hard brake pedal 2nd April 2015, 2:59 pm

mikewazowski

7 Re: Hard brake pedal 2nd April 2015, 3:17 pm

Stu

8 Re: Hard brake pedal 2nd April 2015, 3:27 pm

Stu

9 Re: Hard brake pedal 2nd April 2015, 4:28 pm

Mr B

10 Re: Hard brake pedal 2nd April 2015, 4:31 pm

Stu

11 Re: Hard brake pedal 2nd April 2015, 4:41 pm

Stu

12 Re: Hard brake pedal 2nd April 2015, 4:43 pm

Mr B

13 Re: Hard brake pedal 2nd April 2015, 4:57 pm

Stu

14 Re: Hard brake pedal 2nd April 2015, 5:06 pm

Stu

15 Re: Hard brake pedal 2nd April 2015, 5:18 pm

Stu

16 Re: Hard brake pedal 2nd April 2015, 5:45 pm

Thermal

17 Re: Hard brake pedal 2nd April 2015, 5:53 pm

Mr B

18 Re: Hard brake pedal 2nd April 2015, 6:07 pm

Stu

19 Re: Hard brake pedal 2nd April 2015, 7:22 pm

Thermal

20 Re: Hard brake pedal 2nd April 2015, 7:35 pm

Stu

21 Re: Hard brake pedal 2nd April 2015, 7:45 pm

Mr B

22 Re: Hard brake pedal 2nd April 2015, 8:03 pm

Stu

23 Re: Hard brake pedal 2nd April 2015, 8:36 pm

Thermal

24 Re: Hard brake pedal 2nd April 2015, 8:38 pm

johnny gtir

25 Re: Hard brake pedal 2nd April 2015, 8:45 pm

Stu

26 Re: Hard brake pedal

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