Braking issue

[Phil Gti 11]

I am ticking off the last few jobs before I get my car ready for the M.O.T. 

I drove it in front of my garage today and noticed the brakes don't feel like enough pressure is being applied.

There are no fluid leaks, fluid level is correct. I tried bleeding them but it hasn't improved.

When the engjne is off and I press the brake pedal it is reasonably firm but doesn't go hard after several pumps of the pedal as I would expect.

Then I noticed a noise, best described a Ssss Ssss each time I press the pedal.

Is this normal or and indication of a failing part.

I have attached a video.

[boldy205 75]

The servo will hiss upon brake pedal operation. Has the car been stood up,/ had new disks/ pad ls recently, therefore the brakes need bedding in?

[Phil Gti 11]

I was towards the end of a full mechanical restoration 2 years ago when I broke my leg. So the car has never been driven, apart from up and down in front of garage this week.

Discs, pads, calipers hoses are all new, as was the fluid.. There is slight corrosion on the discs, which is being ground away slowly driving it by my garage. 

Should the pedal not go hard after 4 or presses? 

[Gohn 68]

don't know what the 'hissing' sound is but it'll just need bleeding again

 

keep topping your reservoir and going around until your peddle feel comes good 

 

sometimes it takes me three full times around before its nice

 

you can get one-way bottles to put on the bleed nipple so you can bleed solo

or a fancy way is to put some pressure in the system which forces the air out much more efficiently (not tried this though)

[PhilNW 44]

Tried a pressure bleeder but found that a vacuum bleeder for best results in getting air out

[Phil Gti 11]

I have a one man, one  way bleed tube/valve. 

Vacuum bleed is good in a garage with an air line.

I have had clutches though where a pressure bleed from the resivior is the only way to bleed them. 

I am going over to my garage again today and will try flush and bleeding the fluid to see if that improves the pedal feel.

[stewal 8]

Pump the pedal with the engine off to release vacuum, then start the engine with the pedal already pressed: if it sinks further the servo is likely ok, if no pedal movement its likely a servo fault.

[Phil Gti 11]

Bleed 3 of the calipers, the fluid was awful. Got to the NSF caliper and the nipple sheared off so easily, it was like it was made of butter! 

This car keeps fighting me. 

On the plus side I fixed the last of the oil and coolant leaks. So one brake caliper nipple isn't much to worry about. 

 

[DamirGTI 342]

With the system properly bleed free from air and pads/disc bedded in , the pedal should feel firm with the engine off .

 

"Fluid was awful" - in which way ? air bubbles or dark fluid color ...

 

If the bleed nipple snapped , but you haven't opened it so it could draw air into the system leave it , and bleed that side via hard line or flexi hose .

 

D

[Phil Gti 11]

The fluid was dark and cloudy. I have already taken the caliper off. I tried heating it with a gas torch and then an easy out which snapped in the nipple. So I will take it to work tomorrow and weld a nut on to it and unwind the nipple out that way.

Edited July 23, 2023 by Phil Gti

[DamirGTI 342]

29 minutes ago, Phil Gti said:

weld a nut on to it and unwind the nipple out that way.

 

Yep , that'll do the trick ! and it's the best method (might need few times try , but eventually it'll let loose) .

 

D