About to do brake fluid change...

[supersport]

I am about to embark on my first ever brake fluid change, gulp. The whole process sounds quite straight forward having had a look at Clarks Garage. Not checked out my hains manual yet but it is bound to be a pile of toss!

Is there anything that I need to keep an eye open for or be aware of before I start?

 

[FistsOfHam]

Always check there's plenty of brake fluid left in the reservoir before tackling each caliper. You don't want it to run dry and pull air in.

Also don't forget to change the fluid in the clutch cylinder as it often gets overlooked and turns pretty horrid after years of neglect. I don't think the clutch fluid is mentioned so much on Clarks Garage or the Haynes manual as the American cars used the same reservoir as the brakes.

 

[supersport]

Clarks just makes mention to bleed the clutch. I hadn't realised that the clutch wasn't fed from the same reservoir as the brakes.

Luckily I have just had clutch cylinders done and the fluid was changed at that point and it was found to be in a very yucky state.

 

[Mike_Pollock]

Soak the bleed nipples on the calipers for as longer time as possible to make sure they are ok.
Mike

 

[robwright]

As Mike said soak the nipples in WD for a good time. Also always use a ring spanner on the bleed nipples not an open jaw as that is one nut that you dont want to round off trust me. In fact always use a ring spanner whenever you can. Open jaw is always a last resort when space is limited.

 

[dave364634]

don't get brake fluid on the paint work!

 

[FistsOfHam]

ORIGINAL: robwright

As Mike said soak the nipples in WD for a good time. Also always use a ring spanner on the bleed nipples not an open jaw as that is one nut that you dont want to round off trust me. In fact always use a ring spanner whenever you can. Open jaw is always a last resort when space is limited.

Open jawed spanners are brilliant for rounding off brake pipe connections (as I discovered). I now have a nice collection of brake pipe spanners of various sizes.

I always use a ring spanner to break the bleed nipple free then tighten it up again gently before attaching the bleed kit. I find it gives you a bit more room to work it free without the pipes and things lingering in the way.

 

[dave364634]

hexaganol sockets are better that bi hex rings.

 

[robwright]

Both have their uses. But in order to crack a nipple and get a pipe on you have to use a spanner. As already posted you can get actual brake pipe spanners which are hexagonal with a slot cut in to get over the brake pipe. Alternatively you can make your own by cutting a slot in a ring spanner with a grinder.

 

[sawood12]

Are you using an E-Z Bleed kit? If not I recommend. Makes the job doable on your own and makes it easy. I got mine for about £16 from Halfords. Just reduce your spare wheel tyre pressure to about 20 PSI.

 

[awattam]

I always use a 1/4 drive 6 point socket just to move the nipple 1/8 of a turn. Then you know it's free and you can swap to a normal spanner. Brake pipe spanners are meant more for the connections on solid lines where there's no way of getting a socket or even a normal ring spanner on because of the pipe.

After bleeding, surround the nipple with thick grease to prevent water from making it's way into the thread and seizing it in place.

 

[Chrishazle]

Just done my 968 - like you, first time I've done a brake fluid change on my Porsche.

If you haven't already got some clear plastic tubing, raid your local aero modelling shop for clear fuel tubing - the larger size (about 1/4" OD) is perfect, they sell it by the metre.

I bought ATE Blue from Euro car parts locally for about £13 - makes the changeout really easy as the colour change is obvious when the new fluid gets to the bleed pipe. They do the same fluid in gold colour - handy for next change!

11mm ring spanner for the bleed nipples - and as everyone says, a good soak in WD40.

Start with the rear nearside caliper, then rear offside. If you've got Brembo 4 pots like the 968, don't forget there are 2 bleed nipples per caliper - you have to do both!

I did mine with the wheels off, made access to the calipers easy.

From the 968UK forum, I've read that it's worth re-bleeding a week and a few miles after changing the fluid - not got there yet, still waiting for the new wear sensors to arrive then I'm changing front discs and pads and will re-bleed then.

 

[robwright]

Generally you should bleed the furthest caliper from the resevoir first then it's opposite corner. Then the other furthest one, then it's opposite corner and as said don't forget the two nipples on the brembo 4 pots. Braking circuits are usually split into two with one circuit opperating opposite side front and rear brakes. This provides redundancy if you lose on circuit you don't lose all braking and can still pull up reasonably straight by braking on opposite sides. I've never looked into it but don't see why it should be any different for the 944. Either way the bleeding principles remain sound. The system holds about 200ml of fluid. Yes that's all. If you put 300 or even 400ml new in to be safe you should get it all. And as Scott said get a Gunson Eezibleed. £15 well spent trust me []

 

[chrisg]

Hiya

Sorry for the delay in replying only just noticed this thread. Most of the relevant advice has already been covered off by others. I notice your car is a Lux so has the single pot calipers all round, I've not experience of working on these but advice would be:

1. As per previous post, make life easier for yourself and purchase an easibleed - it's OK doing the pedal to floor, 2-man process, but this pushes the Master cylinder seals into unused parts of the bore (advice from a Porsche expert) which can create issues.

2. Have the car level and on 4 x axle stands with the wheels off.

3. Buy more brake fluid than you think you need -nothing worse than running out half way thro' !

4. Buy appropriate brake spanners and don't be afraid to use a heat gun/ blow torch on the calipers before attempting to 'crack' the bleed nipples for the first time- if they're rusty or corroded use a full ring spanner and/or socket for the 'cracking'.

5. Whilst you've got the system 'apart' and bleeding the brakes what condition are the flexible hoses in ? Might be worth changing these whilst you're at it ?

6. Ensure youv'e got a good supply of Brake cleaner for hosing down any leaks or spillages onto pads/discs/ hubs etc.

7. If by chance you shear a nipple off/ round the edges off - DON'T PANIC - most good garages/ engineers have plenty of tricks and kit to remove them without the need for a new caliper - trust me, I've done this on numerous occasions...

8. Good luck !

Yours

Chris

 

[supersport]

Thanks guys, plenty of good advice there.

I was planning on using an easy bleed kit. The job doesn't sound to scary as long as I can get the bleed nipples undone without cocking it up.