Brake pads and fluid change question.

[Locknut]

eltax91 said:

Genuine question.... Why?

He's right. It's better to empty the reservoir with a suction device and refill with new fluid before bleeding. Firstly you can empty the reservoir completely (don't touch the pedal) before refilling rather than mixing the old and new fluid as you keep it topped up while pumping. Secondly some master cylinders can be damaged by excessive pumping, in fact you should try to use half strokes while pumping. This prevents the seals being pushed into part of the cylinder that is not normally used and which could be a little rough.

Once upon a time it was possible to buy blue fluid as well as the normal amber fluid. You could alternate the colours so when bleeding you knew the fresh fluid was through when the colour changed. I see that Ate blue fluid is still on sale on eBay but it's not worth the money they are asking.

[BritishRacinGrin]

Don't forget to get the clutch done while you're down there, there's a good chap. Clutch fluid generally has a tougher life than brake fluid.

[Matt Seabrook]

I have been a mechanic for 29 years and have always changed brake fluid every couple of years. As has been said its part of manufactures recomendation. We see on a regular basis the damage caused by not changing brake fluid. Seized calipers brake hydraulic systems rusting internally damaged ABS modulators. IMO if you can do it your self for a few pound its barmy not to. Even if you can't get a garage to do it for you. It shouldn't take more than about half an hour to change as long as bleed nipples are of and cost about £30-35 at an independent garage. Also make sure you use the correct brake fluid for your car as there are different types now and even ESP specific brake fluid. Aso bleeding the clutch as mentioned.

Brake fluid is hydroscopic so will adsorb moisture so at two years it's likely to be just about OK at three years it's likely to be below spec. Do you really want to run the risk of loosing your brakes when you most need them? We have all heard of the chap that has never changed the engine oil in his car for ten years etc. the owner thinks he has saved him self a fortune and been very smart. What the chap hasn't told you the car is drinking a litre of oil every 600 miles, knocks when he starts it up is down on fuel consumption. He has had to replace the cat on the last couple of MOTs as its failed emissions. All on a ten year old car.

We all like to save money where we can but not changing brake fluid is penny wise pound fool IMHO

[powerstroke]

eltax91 said:

powerstroke said:

Just one thing best to empty the reservoir first then fill with new fluid then bleed the system ...

Genuine question.... Why?

I was taught the above way when I did my basic vehicle maintenance course at the local college.

Because the fluid in there is more likely to be contaminated with moisture and how would you be sure you had removed all of it not just ended up with a mixture also but not always the new fluid looks different so you can see it when you bleed, remember people who can do do ,others teach!!!

[Jakg]

BritishRacinGrin said:

Don't forget to get the clutch done while you're down there, there's a good chap. Clutch fluid generally has a tougher life than brake fluid.

I don't see how this is the case - brake fluid has a boiling point, which lowers as it absorbs more water - i.e. they fade quicker.

Clutch fluid doesn't (or shouldn't!) be getting hot so I can't see the point - although obviously new fluid is better than old! In my car (MG ZT) the master cylinder (and reservoir) for the clutch is on top of the pedal (i.e. buried way up inside the dashboard) and the bleed nipple requires a little disassembly in the engine bay so it's not trivial to do. I've replaced it all anyway...

Locknut said:

Once upon a time it was possible to buy blue fluid as well as the normal amber fluid. You could alternate the colours so when bleeding you knew the fresh fluid was through when the colour changed. I see that Ate blue fluid is still on sale on eBay but it's not worth the money they are asking.

ATE Super Blue gets great reviews and is very inexpensive (Around £12 per litre - even the cheapest OEM stuff is still £6.50 a litre) when compared to the other expensive alternatives (i.e. RBF660 et al). And being blue makes it very easy to see when you've finished getting all the old brake fluid out. It's just a shame the "gold" version they sell in the US isn't really available over here (it's identical, just a different colour so you can use it after you've used the blue to see when you've got all the old stuff out).




I change the fluid in my car every 2 years because, well, why not? It takes less than an hour (I'm very slow!) and the total cost is less than £15 (and even then you'll have loads of fluid left over) - all you need is a spanner, some hose and an assistant (i've not had much luck with the pressure bleeding kits).

My Girlfriend has a shed of a VW Golf MK4 (185k miles, 16 years old) and the fluid that came out of that was green (!). It was a bit of a faff to bleed (all 4 calipers done, brakes spongey has hell, then I find you have to bleed the master cylinder... with 2 bleed nipples), but afterwards both the brakes and clutch (they share the same reservoir) felt noticeably better.