Bleeding brakes

[h_____]

Folks,

Can anyone quickly detail the quirks I need to remember when bleeding the brakes. I know the basics, but cant remember the oddities of the RS and pressurised system. I need to lock the overflow pipe I think (where is it?), and what else?

Need to give them a quick SRF refill before Oulton this week.

regards

hugh

 

[964RS]

Hi Hugh, I speak from experience. Before you start the procedure - with the engine running pump the brake pedal a few times and make a mental note of the number of pumps before the accumulator pump kicks in. You can hear it whirring as it builds up pressure. You'll thank me for this later when you start thinking 'Is the accumulator pump kicking in earlier than before'. [8|] If you are using the spare tyre method - make sure you have got enough pressure in it beforehand and then lower it to the pressure limit recommended with the kit. The vent hose is under the front hood and is a cloth braided hose heading backwards, towards the driver, and then down. It dumps brake fluid behind the front left wheel in the event of over-pressurisation. Clamp the vent tube with a 'hose-clamp' - better known as mole-grips. [] Look for the vent pipe exit and put a jar underneath it - 'cause you may forget to clamp with repeated cycles. Will scuff up the hose a little but there are not many garage queens in this register. [] Change the SRF for AP660. [8|] Do not drain the fluid totally - not always a problem - but it does introduce air into the system. Remember - each corner has TWO bleed nipples. Doesn't really matter which order you bleed these - I start with the outer one each time. Use a ring spanner on the bleed nipples - don't be tempted to use 'Ein Englander'. Start at the rear right-hand side, then rear left, then front right and finally front left. i.e. Start with the furthest away from the reservoir. As you bleed each nipple you will get air bubbles coming out into your jar. Continue for a while as you will not see the smallest air-bubbles. Try not to let the fluid level drop below minimum level in the reservoir. Top up as necessary - after releasing the pressure. You're likely to use at least a litre for a full system bleed - perhaps 2 litres. Get plenty of back-up supplies - a lot easier than trying to find the fluid you want on a Sunday at 4pm. [] You may have to repeat the cycle a few times to get a hard pedal. (Good opportunity to bleed the clutch cylinder too - but I've never done that myself).  []

 

[964RS]

PS: SRF doesn't mix with other brake fluid as it's synthetic so you're stuck with it or you'll have to do full purge - about 4(?) litres. [8|]

 

[h_____]

Thanks, thats what I was after. Car already has SRF, so thats fine. Much appreciated!

 

[ChrisW]

I agree, I've just had to put another set on the N-GT --- even down to rear discs and handbrake pads [:-]

 

[Hacki]

ORIGINAL: ChrisW and handbrake pads [:-]

Had to replace mine after 18 yrs, due to age, not wear.... So we´ll be fine for the next 20 yrs!

ORIGINAL: 964RS You may have to repeat the cycle a few times to get a hard pedal.

Yes Rgds, Hacki

 

[h_____]

ORIGINAL: ChrisW I agree, I've just had to put another set on the N-GT --- even down to rear discs and handbrake pads [:-]

Really Chris, I thought you did yours at Spa last year? I'm treating Sarah to a night in the garage tonight to do this. []

 

[Steve Brookes]

I changed the front discs twice last year! They were shot and juddering like crazy after half a dozen track days. Below is my DIY write up for anyone who wants to change their handbrake shoes themselves: http://www.964uk.com/Documents/964%20handbrake.pdf

 

[Melv]

Steve........arte you using OE discs?? You need to change your braking style......

 

[Steve Brookes]

ORIGINAL: Melv Steve........arte you using OE discs?? You need to change your braking style......

I think I'm just rubbish at braking Melv []. I use standard C2 discs (made by Sebro, solid and smaller than yours). There was a thought from others more knowledgeable than me that using aggressive pads on the front (Pagid RS15 greys) and standard pads on the rear lead to the fronts overheating. I've since switched to less aggressive pads all round (Hawk blues) and the signs are good so far. Luckily C2 discs are a lot cheaper than yours at around 50 quid each.

 

[Melv]

Short, sharp braking is the answer -mine do at least two years of track events.....

 

[Steve Brookes]

ORIGINAL: Melv Short, sharp braking is the answer -mine do at least two years of track events.....

Will try it out at the weekend []. The other thing I forgot to mention is that I'd done 4 trackdays on the new discs with no problems and then lent the car to Marcus Carniel to practice at Silverstone for his upcoming race....that's when they started juddering....it makes me wonder if his use of LFB might have killed them...[&:]

 

[Melv]

ORIGINAL: Steve Brookes .....and then lent the car to Marcus Carniel to practice at Silverstone for his upcoming race....

Nuff said!![]

 

[964RS]

ORIGINAL: Steve Brookes his use of LFB might have killed them...[&:]

LFB = WTF = FFS = £££ [] [][][]

 

[carreraboy]

ORIGINAL: Hacki

ORIGINAL: ChrisW and handbrake pads [:-]

Had to replace mine after 18 yrs, due to age, not wear.... So we´ll be fine for the next 20 yrs!

ORIGINAL: 964RS You may have to repeat the cycle a few times to get a hard pedal.

Yes Rgds, Hacki

Your pads last so long because you have a Tiptronic Hacki?

 

[Melv]

Marcus needs to learn to heel-and-toe!!!

 

[Melv]

ORIGINAL: carreraboy Your pads last so long because you have a Tiptronic Hacki?

Only coz he doesn't need to do handbrake turns out of the gravel...........

 

[Hacki]

ORIGINAL: carreraboy

ORIGINAL: Hacki

ORIGINAL: ChrisW and handbrake pads [:-]

Had to replace mine after 18 yrs, due to age, not wear.... So we´ll be fine for the next 20 yrs!

ORIGINAL: 964RS You may have to repeat the cycle a few times to get a hard pedal.

Yes Rgds, Hacki

Your pads last so long because you have a Tiptronic Hacki?

Normally I never use the handbrake, neither in the Cup nor in the 993 Convertible. Ref disc / pad wear: I´m with Melv. After changing the driving style, the wear was reduced to less than 50% of what it used to be. Rgds, Hacki

 

[h_____]

OK to update thsi thread. For those of you at the RS day, you will know, I've still got brake issues, which certainly hit my confidence on the day. Symptoms are as follows. Pedal has excessive travel (judged by checking a few other cars), and not very hard, although it didnt change throughout the sessions. The other issue is when the car is cold, the first stab of the pedal (always in the paddock) sees a slow return of the pedal. I'm starting to think that I may need to do 2 things. Firstly have the master cylinder out and check the seals (in case fluid is getting past a bit), secondly consider rebuilding all the calipers (as I've not done it since owning the car!) Oh and the compressor runs for a slightly longer than usual too. Anyone got any other suggests, as to what might cause this. I'm sure I need a new set of pads now, so will do that at the same time. I swear the car will be 100% fighting fit for Abbeville!!![]

 

[Hacki]

Did you repeat the bleeding cycle? ....several times, as Paul said? Hacki