Bleeding brakes?

[Davey240]

Hi Guys,

Just wondering what your thoughts are. I have owned my 240GL for almost 15 years and it now has 63k on the clock. I`m ashamed to say that other than changing the pads i`ve never done any other work on the brakes i.e. not changed the brake fluid!. I know that it should be done but i`m a little concerned after reading some of the previous posts that i`m going to make a whole lot of bother for myself e.g. rounding or snapping seized bleed nipples and then needing new calipers etc. So what are your thoughts should i change the fluid or leave well alone?
Thanks a lot.

Dave

[Eddy Matthews]

You should certainly think about changing the brake fluid as it's hygroscopic, ie it absorbs water over time.... This lowers the boiling point of the fluid which can result in total brake failure in the worst cases!

Of course there's a chance that bleed nipples may snap off etc if things haven't been moved for some time, but that would be a small price to pay for your or your families lives!

Regards
Eddy

[john h]

Agreed.

To give you the best chance, clean all of the bleed nipples thoroughly with a wire brush, then apply a WD40 several times over the course of a week before you try to undo them.

And to avoid immobilising the car, check all nipples will move before you release the fluid

John

[Clifford Pope]

Don't drain out the fluid, just connect a tube to each bleed nipple in turn and pump until the fluid runs clear. that way you never have to actually bleed them.

Tips:

1) NEVER pump the pedal down any further than you do in normal braking. Do a series of small movements to bleed the brakes. Best of all is to use an Easibleed with very low pressure and just open each nipple in turn.
Obviously remember to keep topping up the reservoir.

2) As well as soaking the threads in advance, use a proper brake spanner or a ring spanner. Apply a bit of force, up to the point before it feels as if it will either turn or snap, and then hit the nipple smartly end-on with a hammer. This usually shocks free any rust, without risk of snapping the nipple.

If you do snap off a brake nipple it's not a disaster - you can slacken a hose joint and bleed out old fluid from there.

[Steve and his 244]

One extra tip - when just cracking the bleed nipples loose, use a 6 sided 1/4" drive socket (8mm) and tweak them in the tightening direction - barely even a millimeter, and then change to loosen and hold the socket on nice an square on the bleed nipple.

Once they have cracked undone, they will easily undo with a normal spanner.

[mikecoppicegreen]

Long time since I bled the brakes on a 240!

If I was changing the fluid:-

1) there are 10 bleed nipples on the thing IIRC. It's going to take some time.
2) get proper releasing fluid - not WD40 - from the motor factors, and douse the nipples several times over the course of a week before you attempt this.
3) a good quality socket fitting the nipples is much less likely to break things, a good ring spanner can also be helpful.
4) this is not a job without risk. There is likely to be muck and corrosion in the system, and it's possible that you will disturb a seal in this process. In most cases that's fine, because the brakes are dual circuit, but the master cylinder can fail and leave you without brakes ( ask me how I know ). You may want to consider inspecting the inside of the master cylinder ( and fitting a new seal kit ) as part of this job, if it's not been done for a good few years.
5) make sure you have plenty of fluid to run through.
6) The haynes manual suggests an order for bleeding the brakes, if I remember rightly. If not, personally, I'd start from the back.
7) if you use a vacuum bleeder ( Machine mart sell one ), then you can suffer from air entering the system around the bleed nipple threads. A little grease on the threads can prevent this ( but it's best not to get grease below the threads ). The advantage of the vacuum bleeder is that you don't need to pump the pedal much at all, and it becomes a single person job.
8) syphon out the contents of the reservoir before you start - wipe out the sediment (if any) as well.

Take your time with it.

Best

Mike

[Steve and his 244]

There are 8 bleed nipples, 3 on each front caliper, and 1 on each rear.

haynes bleeding order is:

1) N/S rear
2) N/S front upper inner
3) O/S front upper inner
4) O/S rear
5) O/S front inner lower and outer simultaneously
6) N/S front inner lower and outer simultaneously

Steve

[Davey240]

Thanks guys for all your words of wisdom and useful tips. Looks like changing the brake fluid is on the to do list once the weather warms up a bit. I must admit its not a job i`m looking forward to as i did once before about 25 years ago on a T reg 244 i had at the time. I did it the old way with me on the nipples ( pardon the pun ) and my brother on the pedal and i remember it being a nightmare!. Mind you i was a lot younger and inexperienced then so hopefully with all your advice and an Eezi bleed kit i should be better prepared this time. Thanks again for all your help,

Dave

[Clifford Pope]

Pressure bleeding is also a one-man job. Don't use too much pressure - just a bit more than gravity.

I think the sequence is important only if bleeding an empty system from scratch.
If you are simply bleeding off dirty fluid I don't see how the sequence matters - at each nipple you just bleed off all old fluid in that particular run. By the time you have done each one, the entire system will be fresh.

Perhaps it's a good idea to press each piston back into the caliper in turn as you bleed that nipple. It would ensure that you flush out the whole cylinder, not just the fluid in the upper section of the chamber.