Bleeding V8 brakes after fitting braided hose?

[Vanya]

Hey guys,

 

Here's one job which is 8000 times more of a PITA than removing my Turbo SE turbo last weekend....who woulda thought?

 

So my V8's front left hose to the caliper split (the rubber one with the metal coil around it). Not surprising considering it's been a garage queen. Lesson learned. Car should be driven more and stood still less.

 

I discovered the issue after the car sharply pulled to the right when braking, and righted itself when releasing the brakes. A leak was identified and I got myself a bunch of braided hoses from SJ Sports cars.

 

Now I've removed the hose in question and fitted the braided one (just doing the one right now). I'm still getting a slight leak at the union between the hose and the bundy pipe collar to the caliper, but perhaps it needs a tiny bit of thread lock...that feels like a lesser problem right now.

 

While replacing the hose a lot of fluid was lost. The reservoir wasn't completely empty but far below the "danger" line - but let's say it's a total FUBAR and air might have gotten in that way. Air also naturally got into the new line, of course.

 

After fitting I tried bleeding at the front left caliper using "conventional techniques" as described in the service notes. Hardly anything came out after some time using a little hose with a one-way valve on it. I then tried using the real old school method - open nipple, push pedal, close nipple, release pedal - with regular hose, the same way I've bled my clutch and that job was a piece of cake even after replacing master/slave/braided clutch hose - it must have taken me and my brother all of 20 minutes.

 

What seems to be the issue with the brakes? I just hear a squelching noise but no fluid is coming? Or does it just take FOREVER? I'm doing all this with the car off and ignition off (not that this should matter with the Kelsey Hayes?)

 

I have a bleeder - one that's powered by a compressor, but I've been scared to use it since I trashed a land-rover slave cylinder a few years back. I think the vacuum was so great it deformed the piston seal...but that could just be me being paranoid. Anyways I might give it a shot and hope for the best. Destroying the Brembos will make me a sad panda if that happens though.

 

Am I missing something here?

 

As always thanks a lot for your advice. I had intended to do this on my Turbo SE first (the guinea pig!) what with its wonderful Delco Morraine system with its detailed bleeding instructions, but as usual with well laid plans...

 

 

[Barrykearley]

Lil bit of clear pipe stuck on the end of the nipple into a bottle with some fluid in it..... The pipe must be in the fluid in the bottle.

Loosen the nipple and just pump until the airs out and you only have fluid in the pipe. Do up the nipple and do the other side

[DaveyT]

Hey Vanya, does it have ABS?

If so, do a general search as I seem to recall seeing somewhere that the " real old school" method won't work for some reason. ( might have been doing my CRV at the time). IIRC it cocks up the ABS circuit somehow...

Edit: this is what I was remembering:

http://www.aa1car.com/library/abs_bleeding.htm

Dave

[Vanya]

Thing is the service notes for the Kelsey Hayes system say "bleed the system the usual way" "using conventional techniques"

Ok just read the link Davey, oh dear hope I didnt get air in the ABS. Oddly though the notes say nothing on this matter if youve replaced the master cylinder which youd think you require bleeding the ABS unit too!

[sailorbob]

Try the "old school" method with a slight variation; push pedal part way, open nipple, push pedal rest of way, close nipple, release pedal. The idea being to try to dislodge the air lock that's giving the problem.

[Vanya]

How long does it usually take to get fluid in the new lines? I remember with my clutch it took no time at all. Maybe I should just try with the compressor straight off the bat?

[Vanya]

Oh damn it one just CANNOT WIN. So I bled the system "the old fashioned way" - built up some pressure, opened bleed with the pedal down, pedal sinks to floor, close bleed. Same way I've done the clutch. Same way it's always described..

 

Took two intervals to get the big air bubble through and feed in fluid. Then came foam, then came tiny air bubbles mixed with...little black bits. Kept bleeding until both air and bits had gone. 

 

After reading for years about this classic bleeding technique I've now seen some keyboard warriors saying that you should NEVER bleed this way - you must ALWAYS have a block of wood under the brake pedal so it doesn't sink all the way into a part of the master cylinder which is seldom used and cuts up seals due to internal corrosion. Because the black bits are master cylinder seals and it will fail shortly thereafter, and now I have to rebuild it.

 

I was thinking it might be remnants of the old brake hose which might have broken down inside and gotten stuck in the caliper.

How come I've never heard of this issue before today? I might have seen one person mention a wood block at some point but it wasn't explained why.

 

Have I just screwed up my master cylinder? 

 

Boy do I feel stupid right now.

[Barrykearley]

If the seals are cut up and knackered - "if" - the brakes will now feel non existant. Press the pedal and does it sink and feel wrong?.

Frankly - if there's corrosion inside the master cylinder that's knackered the seals - it needed rebuilding anyways.

In all the garages I've done electrical works in - I've never seen the block of wood under that pedal.........

[sailorbob]

Start the engine and apply lots of pressure to the brake pedal, if it stays solid and does not sink then the master cylinder is OK.

[Vanya]

Hey guys, thanks for the feedback.

 

Well it was my better half that was in the car but she said the pedal became rock hard after all the air had disappeared. She didn't mention anything about the pedal sinking before I'd opened the bleed nipple. I haven't checked pedal feel for myself yet. We're gonna check whether any air is coming up at any of the other wheels then we'll take it out for a drive. After today however we were knackered so leaving it for some evening later in the week.

 

The brakes were last drained and refilled in august 2011 so it's been some time but the care has, other than that, always been extensively serviced. Would seem odd for there to be corrosion in the master cylinder.

 

I've heard of some people having "bits" from old brake lines that brake down internally. Could the stuff have been remnants from my old cracked line stuck in the caliper?

 

Here's a pic of the fluid that came out:

 

 

The fluid in the reservoir was really clean from what I could tell though. 

 

 

 

[Barrykearley]

Exactly as sailorbob says - run the car and press that pedal.....

The seals stop fluid leaking back past..... If they are shagged - fluid will leak past the seals - the pedal will sink - and often fluid will run down the pedal.

Bits of junk could be from anywhere - it's always worth a bleed out of the fluid.....

[sailorbob]

If it's not been done since August 2011 I agree with Barry that you bleed the other three lines.

[Alex Carter]

When I did my over haul I too had issues bleeding the pedal didnt feel right after the first attempt . I did the old school way of bleeding with a mate I don't like the air bleeders I've witnessed a brake resovoir explode because of the pressure. I started on the furthest caliper from the servo first and work towards it. Then drove it and then bled it again but fronts first this time and it sorted out the pedal feel.

[Vanya]

Hey Alex,

 

I prefer tried and true methods myself - I've also had mishaps with pressure bleeding, so I thought the classic method ought to be safe®. I'll go out for a drive with the car later today (weather permitting) and see if the pedal holds under pressure. I'm really hoping I don't have to replace the master cylinder seals, although I've gone through worse. Luckily some chap on here discovered it's actually from a Pegueot 406 so sourcing a new one (or just replacement seals) shouldn't be too hard.

 

If the black bits indeed are my seals then I might as well replace the whole thing due to internal corrosion (unless I hone the bore, which might be worth it).

 

Thanks once again for chiming in with tips and advice. It's much appreciated. 

[fjmuurling]

I'm thinking of installing stahlbus bleeders on my car

 

www.stahlbus.de

 

 

[ramjet]

Interesting. The 'old school' methods on here differ from what my dad taught me. (He did train as a mechanic)

I have always done the following on many different types of cars and never had an issue.

With system all tight and closed, get assistant (clothing is discretionary) to pump brake pedal until it comes up hard if possible.

Gently undo the bleed valve while the pedal sinks to the floor.

Tighten bleed valve.

Repeat until no air comes through pipe on bleed valve.

IMPORTANT: Keep an eye on the reservoir that it does not empty.

If the pedal refuses to go hard with repeated pumping, proceed with undoing the bleed valve and eventually the pedal will come good.

[Vanya]

That's EXACTLY the way I do it. My pedal is now rock hard. Except apparently one must close the bleed well before the pedal hits the floor. 

[ramjet]

I have heard the 'block of wood theory' as well and have never lost a master cylinder either. I may have just been lucky.

[sailorbob]

In many years of bleeding brakes the traditional way I have never had and issue with pushing the pedal to the floor.

 

 

Now, I'll regret saying that when I do my next bleed   

Edited June 22, 2015 by sailorbob

[Alex Carter]

There are stories of people depressing the pedal and so say flipping the seals but I've never had an issue doing it old school .

[Vanya]

The Hayne's manual for my Ford Focus mentions that - so "NEVER EVER PUSH IN CALIPER PISTONS WHEN CHANGING PADS!!!!" -.....errr..how else? 

[Barrykearley]

Ahh that's an easy question.......

1 You take it to a car dealers

2 when in the workshop they remove pads.

3 massive pair of grips - squeeze back go the Pistons.

4 put back together

5 bleed brakes

6 bleed customer dry.......

[steve930]

How old is the focus ?Some of the newer canbus Vehicles need the relevant ecu Control module being told the caliper pistons are gonna be pushed in before you actually manually do it,otherwise it causes all sorts of problems. Especially if the car has electronic handbrake 

[Vulcan Grey]

many rear brake pistons have to be rotated back in due to the mechanical hand brake mechanism. 

[Vanya]

OK I did the remaining (rear and mid-section) hoses today, not too bad, but now I'm stuck bleeding the system. How long should this take using "the manual two man method" - I bleed at a caliper, 2 bubbles come out. Bleed it again, nothing. Move to next caliper, two bubbles, next time, nothing and so on - but the bubbles never seem to cease! We then started bleeding from the caliper furthest from the master cylinder - rear right, rear left, front right, front left - extracting air along the way. The bubbles seem to move about doing it it this way, as staying at the same cylinder doesn't yield more air - one needs to return to it after bleeding elsewhere...

 

I've got the rear end jacked up higher than the front to aid air escape. At one point the ABS unit (Kelsey Hayes) started cycling but then the battery died so no idea what that could've been about (the ignition was off during the whole procedure) - anyhow battery on charge now, car still up on stands overnight will give it another crack tomorrow. I notice the pedal is feeling firmer and firmer with less travel to hit "rock" - but I'm still a bit confused - we must have spent 2 hours bleeding it, and there's still air in the system somehow.

 

Am I doing something wrong? As far as I can tell all connections are tight, no leaks anywhere....