Calling all experts - spungy brakes on leon tdi!

[Zeap101]

Hi peoples

Can you help?

I have an 04 TDI Leon Cupra and since buying the car i've never been impressed with the brakes. I've just upgraded to 2500's and 312mm discs. Trouble is im still not that impressed.

When I pump the pedal (engine running) it's goes stiff briefly but when my foot's kept on, it sinks to around half way. When engine is off it holds ok. Basically the brakes don't have much initial bite ever! I had a 05 megane and the brakes used to put you through the windscreen - I want that again!

I'm thinking brake fluid change? but i've been reading threads and i'm worried Re: master cylinder???

When bleeding the brakes do u need to also bleed the master cylinder? How many bleed nipples in there on it and how easy is that that to do? What about ABS system too? Oh and also how much (ml) of fluid would i need for a complete flush?

Thank you very much for any help!
Rich

 

[rallynut]

have a search on here there is a vacum hose or joint that leaks as it comes out of the vacum pump,leads to soft brakes common on golf tdi's i think

 

[james walker]

yes you need to bleed the 2 nipples on the mc, if you didnt then thats where the problem will be

just pay a local garage to bleed for you, 40quid odd including fluid, supply your own and go for motul rbf600

 

[Zeap101]

thanks guys

Where are these bleed nipples exactly on the MC? i think ive seen one which is under the resivour?? Also im sure my resivour cap keeps coming lose on its own? and how much fluid would i need for a complete flush? I have tried searching but can not find the answer.

Any adeas? Any help would be great!

 

[Cupra_R04]

i had this problem with my lcr and it was the master cylinder needing bleed. Facing your engine bay look to the right hand side of the brake fluid cap. There will be 2 nipples with caps on them. Probably need an extension bar and small rachet. Would make it easier. I think from memory that the nipples are 7mm

Hope this helps Mark

 

[Zeap101]

Cheers mark

Did your res cap keep coming lose? It it just the air unscrewing it? I'm def not losing fluid and the break do work fine. I think i'll just get it into a garage and let them sort it (even though i hate spending money on labour costs!)

Oh and does anyone know how much fluid i would need in order 2 do a fluid transplant?

 

[cocadave]

how long ago did you change the discs and pads?

 

[Zeap101]

Just the other day. The propblem was there prior to that mind. I was just hoping upgrading to 312mm discs and 2500 pads was going to solve it.

But im not as satisfied as i hoped to be!

 

[cocadave]

I would suggest leaving them a good few hundred miles to bed in, mine took a couple of weeks to bed in but when they did they are really worth.

 

[JamesL]

bleeding his brakes wont make it any worse, so unless your really averse to spending the money its something that could be done anyway. Upgrading your fluid is never going to be a bad thing and if the reservoir cap is unscrewing itself then the hydroscopic fluid will be taking in air anyway.

 

[KEEPitSTUPID]

bleeding his brakes wont make it any worse, so unless your really averse to spending the money its something that could be done anyway. Upgrading your fluid is never going to be a bad thing and if the reservoir cap is unscrewing itself then the hydroscopic fluid will be taking in air anyway.

Hydroscopic fluid?

A hydroscope is a piece of equipment used for viewing things underwater, do you mean the brake fluid absorbs air therefore making it able to be compressed therefore bouncey feeling? If so is this not just age? As the resevoir caps have breather ports on them anyway in order for the system to work.

 

[BoostHard]

He means hygroscopic,

 

[ManOnTheMoor]

I have 05 tdi and the cap has previously unscrewed. Blamed garage after service as noticed undone but did it to me also after disk/ pad change. As the fluid is hygroscopic I.e. absorbs moisture and lowers boiling point plus the unknown period of time cap loose, I elected to pump fresh fluid thro the system - fluid change is recommended every two years....I upgraded to 312 and took approx 100 miles of bedding in before I used in anger- defo made a difference. I was given set of new yellow stuff pads which are ok but work much better once given a pre brake - need a bit of heat to work better, which is not always the best when muppets pull out in front of you without looking....Will choose different pad next time but hey....they were free so can't complain