[Mk2] [Turbo] At wits end bleeding brakes (Warning: Essay ahead)

[toxo]

Over the last 3 weeks I've been refurbishing my brakes, changing pads & rear discs. This started as one rear brake binding, then once I saw the state of it I investigated the other rear brake, discovered it was on the way out as well, and decided while I was there I might as well do the lot. My car is marooned at work with no brakes atm, so I have only been able to do things to it during my lunchbreak or in the hour of daylight after work finishes! This has involved a lot of waiting around for mail order bits to arrive due to a lack of transport. As you can imagine, once I'd got it all back together I was rather eager to bleed the brakes and get behind the wheel again!

I knew the car had DOT4 fluid in it, so I nicked a bottle of Lucas DOT4 off my dad and went at it. This was my first bleeding procedure:

Starting with passenger side rear wheel, then drivers rear, then passenger front, then drivers front. Mate in the driver's seat. Me at the relevant wheel. Loosen bleed valve, push brake pedal. Tighten bleed valve, release brake pedal. Repeat until plenty of fluid comes out of bleed valve. Check reservoir every 10 pumps or so to make sure we don't let any air in that way. Once brake fluid is flowing, tighten bleed valve, pump pedal 6-10 times until stiff again, and then with pedal depressed, release & tighten valve again. Repeat with other 3 wheels.

Once I'd done the above, the pedal was very spongey and the brakes didn't function. So, I went round again, making sure I hadn't missed anything. All seemed fine. In the course of these 2 bleeding sessions it ate the whole 500ml of Lucas DOT4 fluid, so I bought a litre of Toyota DOT5.1 for a fiver off eBay. I hadn't intended to buy Toyota branded as I figure brake fluid is all much the same as long as the DOT value is right, but it happened to be cheap.

Mildly peeved, I hitched a lift to Halfords to get a one man bleeding kit. I checked and the eezibleed kits that use pressure from the spare tyre don't work on my car as it has a pop on cap on the brake reservoir rather than a screw on one, so I bought one of the kits which has a pipe with a one way valve in it. Back I go and this lunchtime started bleeding again.

In the same order as the first time round, attached pipe to bleed valve, loosened, pumped until no bubbles were seen in the pipe (which is about 1ft long) as per instructions. Did the same thing with pumping the pedal a few times and then releasing / tightening the valve. All 4 wheels later, pedal is even softer than before (??????) unless you pump it 4 of 5 times at which point it stiffens up again for ~10 seconds.

At this stage more than mildly peeved as I was meant to be going to the cinema tonight, and having run out of lunchbreak, I decided to give it another going over after work. So I ran through the whole procedure again, which has now used the remainder of my DOT5.1 fluid. Surprise surprise, the braking system is still just as useless and still only stiffens up when you pump it!! I AM NOW VERY ANGRY!

I have now bled my brakes following 2 different procedures FOUR times!! Where in the name of flange am I going wrong?! Have I just got a brake system that's posessed by the devil?

[GhostWKD]

got leakage?

or other than that... when bleeding is the bleed nipple right at the very very top of the caliper? as if not this wont bleed properly

[toxo]

I had thought that... I have been checking under the car while someone's been pumping the brakes and there's no fluid dripping anywhere but I suppose it could be a very small leak!

Yes, the bleed nipple is at the top of each caliper (ergo I have put the calipers back on the right sides!!)

[simmo490]

question why did u start at the back passanger first.

sometimes draining a system of flud can show up weak cylnders, also did u say u revuilt calipers??

[toxo]

I believe you're supposed to start furthest away from the master cylinder and work your way through calipers til you get to the closest one. In a MK2 turbo the brake reservoir / cylinder is directly in front of the driver, so that makes the passenger side rear the furthest away.

I had thought that it could be the cylinder on the way out. I did rebuild the calipers, so it should have taken (and has) a lot of fluid to refill them I would assume.

[simmo490]

ok mate thats cool, you know the principle then

i have done this before and it shows up a weak cylnder and has stumped me in the past but not saying thats your problem.

have you tried pressure bleading them,

pump them till there rock hard, as fast as u need to get it hard (ohh i say) now with your mates foot FIRMLY on the pedal, crach off the first bleed nipple, do this as many times as it takes to get air from each one. see if that works mate

simmo

[simmo490]

also another way is to leave all 4 bleed nipple open over night with card or pots under them, leave the fluid cap off and just fill it up. that will also bleed air out but shouldnt empty the ressy

[toxo]

That's a non starter cause I only have 2 axle stands so I can't have all 4 wheels off at once I might just give in and take it to a garage...

[simmo490]

i dont think there is anything wrong with ure method. dont pay a gargage to tell u whatu al ready know

[JOHNM400]

Ive had this problem before. My Citroen Van i used for valeting was a right pain in the backside. I went through about 3 LT's of brake fluid before i got them right. Sometimes theres air thats trapped in one of the pipes and it takes ages to get it out. Just keep at it and eventually the pedal should come back up. Make sure youve got plenty fluid. Its only cheap just go to the local car shop and buy some. At worst you may of flipped a seal in the master cylinder but hopefully not.

[spannerman]

I'd say the seal has flipped in the master cylinder, bleeding the brakes shouldn't be such a big ordeal.

[toxo]

Cockit, I was hoping that wouldn't be it. Oh well, not the end of the world I suppose, just another week or two without a car!!

[davyboy]

I'd say the seal has flipped in the master cylinder, bleeding the brakes shouldn't be such a big ordeal.

I'd agree with spannerman, same thing happened to me

[Monaco]

When I changed a caliper on my old NA, me and a mate had mega issues bleeding the brakes. (Same sort of issue as you did where we'd bleed each caliper until only fluid came out, but the pedal still felt spongey afterwards.)

We ended up bleeding it using a short plastic tube held in a jam jar of brake fluid (seeing as though we didn't have any one way valves or pressurised bleeding kits).

The other trick we used was to jack the relevent corner up, remove the wheel, and then lower that corner right back down again, before bleeding.

Looking back now it seems a little non sensical, but that was the only way we could get the brakes to bleed properly.

[magic_alex]

i currently have this exact same problem i beld my brakes three times last weekend after refitting standard suspension and still have a brake pedal of sponge - no amount of bleeding seems to help my pedal travels half way down before the brakes take effect its not good!

[simmo490]

When I changed a caliper on my old NA, me and a mate had mega issues bleeding the brakes. (Same sort of issue as you did where we'd bleed each caliper until only fluid came out, but the pedal still felt spongey afterwards.)

We ended up bleeding it using a short plastic tube held in a jam jar of brake fluid (seeing as though we didn't have any one way valves or pressurised bleeding kits).

The other trick we used was to jack the relevent corner up, remove the wheel, and then lower that corner right back down again, before bleeding.

Looking back now it seems a little non sensical, but that was the only way we could get the brakes to bleed properly.

u sound like u resorted to using tube and jam jar? this is by far the best and origional method mate and i am supprised u didnt do this at first as this is the natruall way of bleeding??

also loweing the corner down, ? surly air goes to the highest point in the system so loweing it down should make a difference, having said that u said it worked so i must have hey.

MR2`s are strange sometimes

[DNOS808]

Hi

One story that I have heard is that in normal use only a small part of the travel of the master cylinder is used. When bleeding the brakes by pumping the pedal the whole travel of the master cylinder shaft is used. The normally unused part of the shaft can corrode and this corrosion can damage the seals in the master cylinder when the normally unused part is used.

Before you dismantle the master cylinder I would put some PTFE plumbers tape on the bleed nipple threads to stop air leaks and I would try a vacume bleeder. They attach to the bleed nipple and suck the fluid through the system. They cost about £50.

Regards
Andrew

[Ja99a]

I have found the easiest way to bleed my brakes was to get a large syringe and suck the fluid through the cliper on each corner until no air comes through.

Perhaps worth a try it always works for me.

[Jimbob]

ABS? its a pain to bleed

[toxo]

No ABS... tbh I have left it alone for a week or so cause I was livid with myself and the car after it ate a brand new front tyre in 2 days, and now I'm skint so nothing's going to get done on it for a fortnight or so. Might try gravity bleeding it on Sunday and see what difference that makes (if any).