Brake fluid bleeding / hose changing advice please

[Rob Clark]

The flame red is getting some braided lines via the group buy so i'm venturing into unknown territory as looking at replacing them myself and never bled brakes or similar before.

Ive done a bit of reading and seen that dot4 stuff is recommended. Car is used for road but do plan on throwing it around the track at some point in the future.
Now reading the various threads it seems you are not supposed to completely drain the brake system as its a pain in the arse to get air out of the callipers ?
Also, I belive brake fluid / coolant is done at 4 years and either 36k or 48k not 100% so is in need of a change as car is currently on 46k and not far off 4years.
The general guide is to swap hoses as fast as possible avoiding air bubbles and with some cling film over the lid of the resevoir (assuming to maintain a vacuum and stopping fluid flowing thru the system).
Are these just screw fit attachments so 2 (each end) per wheel / line (new lines not arrived yet). Once all hoses have been changed im guessing there must be some bleed point / nipple available to purge air in the system on each line to a wheel which can then be used (with cling film removed and whilst topping up resevoir) to bleed the old fluid thru the pipes thus flushing it ?
For this reason im assuming you must have to mix old / new fluid in resevoir for bleeding and that the engine must be running to bleed as system has abs ?

Thoughts please as when i do get round to it I shall take pics and knock up a guide as seems to be a fair amount of info but in various places.

 

[MRBILLYUK]

Personally i change the brake fluid every 12 months .I usually use castrol response , but any dot 4 will do .

Like you say . Once you've changed the hoses you will need to bleed the system to get out the air . Do it with the engine off and never drain the whole system . It takes 1 litre , but get 2 litres just in case of any spills . As you bleed some of the old fluid out , keep topping up with the new fluid , eventually you'll have replaced all the old with the new .

I use a small funnel in the top of the brake fluid reservoir so its easier not to miss the top of the res , i also put rags around the top of the res in case of any spills .

You can get eezi bleed kits for one man bleeding . I just use a small bit of rubber hose i got from a local motor accessory shop into a jar filled with some old brake fluid , keep the end of the hose below the level of the old fluid so it can't suck back any air . Then i pump a few times , top up , pump , top up etc ..... or get a mate to help , one pumps the brakes a couple of times the other cracks the nipple open and lets some of the old fluid out , then tighten up the nipple when the brake pedal is at the bottom . Always keep your eye on the level and keep topping up .

Be careful with the bleed nipples . They can be tight , and they can and do snap easily if you over tighten them .

 

[Steve]

Im having my fluid changed Sat am for castrol response dot 4, car has only done 11k but want to see if i get any improvement.
£30 with me supplying fluid, not worth getting hands dirty & i get a stamp in the book

 

[Rob Clark]

i dont think its mandatory on the 12, 24 36 or 48k services but is advised at 4 years which im fast approaching. Had forgot about having book stamped tbh but, like brake pads, is one of those things i;d like to do but poss say im never doing again afterwards. Has anyone got any description or a pic of where the bleed points are as not entirely sure what im looking for.

 

[Steve]

Bleed nipple on each caliper, with dust cap, 7mm i think.

 

[Grandpa Munster]

Bleed nipple on each caliper, with dust cap, 7mm i think.

8mm.

 

[Grandpa Munster]

Get an eezi-bleed kit, probably £15, 2 litres of brake fluid, £12, job done.

You can guarantee you will need to bleed the system again, if you buy the above, you will be geared up to do it as many times as you like.

 

[youngsyp]

It's strange that you guys all use DOT 4 fluid as, DOT 5.1 fluid is specifically designed for ABS cars ?!
The only reason I'd be using the DOT 4 over DOT 5.1 is for the higher boiling point the DOT 4 usually has, over the DOT 5.1. This is only really useful on a track though ?!

Anyway, just to reiterate some of the points above.

You should never drain the brake system dry as, you could damage the master cylinder piston etc...
Always use a fresh bottle that has been un-opened as, brake fluid is hydroscopic meaning, it absorbs water from the air. Obviously, water in the brake system isn't good.
When you're bleeding the brakes, start at the caliper the furthest away from the master cylinder, and work back. This normally works out as follows: back passenger side then back drivers side, then front passenger side, and finally front drivers side. This is by far the best way of getting all the air and old fluid out of the system.
With regards to teh old fluid, if you use a clear hose on the calipers bleed nipples, you'll normally see a colour change from old to new fluid. It should be pretty obvious when all the old fluid is out of the specific corner.
To do the job properly, you'll need 2 people or, a vacuum bleeder.
If you're going to do it with another person, get them to press the peddle down, open the bleed nipple, wait for the fluid to go through and with them still holding the peddle down, do up the bleed nipple. This will stop any air getting drawn back through the bleed nipple.
Also, put a level of brake fluid in the container you're bleeding into so, the hose connected to the bleed nipple, has even less chance of sucking up air.
The cling film over the fluid reservoir is a nice idea but, it doesn't actually do anything.
Finally, when you tighten the banjo bolts for your new brake lines, don't tighten them too much. The will shear off !

HTH.

Paul

 

[Steve]

The renault fluid is dot 4 :S

 

[youngsyp]

The renault fluid is dot 4 :S

Well, they are French.



I'll get my coat.....

 

[Rob Clark]

excellent stuff ty.
so bleed points on callipers = good. im assuming dust caps and some form of nut to loosen to open a valve ? also, if using a pipe (i hadnt thought of this) what sort of internal diameter (guessing 3-5 mm) that can be uses as a run off

 

[youngsyp]

excellent stuff ty.
so bleed points on callipers = good. im assuming dust caps and some form of nut to loosen to open a valve ? also, if using a pipe (i hadnt thought of this) what sort of internal diameter (guessing 3-5 mm) that can be uses as a run off

You actually undo the bleed nipple which, will have a hex shaped part on it.

As for the pipe/hose, see what will be a tight fit over the bleed nipple.

 

[Grandpa Munster]

excellent stuff ty.
so bleed points on callipers = good. im assuming dust caps and some form of nut to loosen to open a valve ? also, if using a pipe (i hadnt thought of this) what sort of internal diameter (guessing 3-5 mm) that can be uses as a run off

Everything you need is in the Gunsons Eezi-Bleed kit, I have one of these.

 

[Rob Clark]

trip to halfrauds req then

 

[bmh.01]

Its definetly DOT4 you want. DOT5.1 has all the problems of it absorbing moisture etc. Can't remember the specifics of it all.

 

[makavelli]

i got this dot 5.1 off yozza for mine:

http://www.apracing.com/roadcar/brakefluid/data.asp?code=cp4510

 

[Steve]

Had mine changed today & all i can say is 4 year intervals are too long.

Fluid looked clean until it was replaced, you could see the difference in the waste bottle when it came out.