P38A 95 DT brake bleeding (or rather lack of fluid)

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J

Jerseyp38

Active Member
Posts
240
Hi,

Well having posted about the brakes before I have been trying to get to the bottom of the problem, seems I have tried so many half measures not sure where to start.

ABS and brake warning light staying on.

have changed the pump and accumulator unit for a known good one and making plenty of noise, sounds like a household heating system pump when there is air in the system.

I have tried to bleed the system on my own with a vacuum pump twice but this morning asked the missus help so could follow RAV, have bleed as per the instructions to the pointy of bleeding the rear calipers and hardly any fluid comes out of either caliper. literally a drip at a time, well maybe a drip a second. This is true of both calipers. Don't think it is corrosion as changed the solid brake pipes nine months ago and bleed easily.

So what to do next?

I don't have a nanocom or anything as cannot really afford it and not sure how much information it will really provide. I have bought a second hand ABS relay block as it was for a manual and on ebay for £30. Also have a second hand PRv (?) valve.

Any help gratefully received as I need a reliable car to get me off this bl**d island for a few days!

I have searched the forum and founds lots of responses but not many with specific guidance for trouble shooting the brakes system.

Cheers
 
Jerseyp38 said:
Hi,

Well having posted about the brakes before I have been trying to get to the bottom of the problem, seems I have tried so many half measures not sure where to start.

ABS and brake warning light staying on.

have changed the pump and accumulator unit for a known good one and making plenty of noise, sounds like a household heating system pump when there is air in the system.

I have tried to bleed the system on my own with a vacuum pump twice but this morning asked the missus help so could follow RAV, have bleed as per the instructions to the pointy of bleeding the rear calipers and hardly any fluid comes out of either caliper. literally a drip at a time, well maybe a drip a second. This is true of both calipers. Don't think it is corrosion as changed the solid brake pipes nine months ago and bleed easily.

So what to do next?

I don't have a nanocom or anything as cannot really afford it and not sure how much information it will really provide. I have bought a second hand ABS relay block as it was for a manual and on ebay for £30. Also have a second hand PRv (?) valve.

Any help gratefully received as I need a reliable car to get me off this bl**d island for a few days!

I have searched the forum and founds lots of responses but not many with specific guidance for trouble shooting the brakes system.

Cheers
Click to expand...
Rears are bled with the ignition on from memory and the fluid should pi $$ out so I would suggest that you remove the nipples and check that they are not blocked. Worth poking something down into the caliper as well. Clamp the flexes to prevent excessive fluid loss.
 
tomcat59alan said:
Rears are bled with the ignition on from memory and the fluid should pi $$ out so I would suggest that you remove the nipples and check that they are not blocked. Worth poking something down into the caliper as well. Clamp the flexes to prevent excessive fluid loss.
Click to expand...

Thanks will give that a try.
 
Hi Tomcat59alan,

Have given that a try and even with the nipple removed and pipes not clamped, only a slight dribble of fluid. Tried turning on ignition and foot on brake peddle and whilst I couldn't be under there at the same time there wasn't any evidence of more fluid coming out. Blockage upstream? Pump not clear of air?

thank you for the suggestion.
 
Should also say have checked the fuses and relays, relays all clicked and gave continuity as per diagram on relay. Fuses all continuity checked and with a fuse tester worked but didn't show much current draw, cannot remember which but think one fuse plugged in gave 250mA and the other 330mA but it might have been 25mA and 33mA respectively. Couldn't do the same test on the 40A fuse but it continuity checked.
 
I had one with blocked nipples,painful, cleared them with a small drill then had to clear the caliper outlet as they were full of crud as well. Guess you could crack off the pipe to the caliper and see if you get any fluid from there.
 
tomcat59alan said:
I had one with blocked nipples,painful, cleared them with a small drill then had to clear the caliper outlet as they were full of crud as well. Guess you could crack off the pipe to the caliper and see if you get any fluid from there.
Click to expand...
Good point, will try that later when I can be under car with a peddle and ignition key operative in the car. Time to take the dog for a walk I guess.
 
Jerseyp38 said:
Good point, will try that later when I can be under car with a peddle and ignition key operative in the car. Time to take the dog for a walk I guess.
Click to expand...
First stage done without pressure then first pressure stage MUST be done to the book. Rears can then be bled. Turn ignition on for four seconds then off and bleed one rear. Repeat ignition and bleed until that line is free of air then repeat for other side. Alan's point about blocked bleed nipples is a good one.
 
Hi Wammers, I have tried to bleed the brakes about 5 times now. First four using different singlehanded tools bodges. But the last time was with a peddle push and key turner following the instructions in RAVE. Am I just not getting enough fluid through? Bleeding the front brakes I used about .25 to 0.4 L of fluid but all points came clear of air bubbles, booster, front boost, rear boost and each caliper. Should I run through more fluid? The ABS light came on first shortly after traversing a very snowy empty car park not done carefully and hence ABS activating regularly. Then the red brake warning light came on as well. My limited knowledge of mechanical things does make me wonder if something is stuck in side the hydraulic booster unit? Or do these units not really fail? Don't believe it was the pump and accumulator but having changed it when I cracked open the union on the side of the hydraulic booster, from the pump, there was pressure there. Shall I have another go at bleeding the front parts of the system again? Thanks
 
Jerseyp38 said:
Hi Wammers, I have tried to bleed the brakes about 5 times now. First four using different singlehanded tools bodges. But the last time was with a peddle push and key turner following the instructions in RAVE. Am I just not getting enough fluid through? Bleeding the front brakes I used about .25 to 0.4 L of fluid but all points came clear of air bubbles, booster, front boost, rear boost and each caliper. Should I run through more fluid? The ABS light came on first shortly after traversing a very snowy empty car park not done carefully and hence ABS activating regularly. Then the red brake warning light came on as well. My limited knowledge of mechanical things does make me wonder if something is stuck in side the hydraulic booster unit? Or do these units not really fail? Don't believe it was the pump and accumulator but having changed it when I cracked open the union on the side of the hydraulic booster, from the pump, there was pressure there. Shall I have another go at bleeding the front parts of the system again? Thanks
Click to expand...

Follow instructions in RAVE to the letter that is all i can say. Red warning lamp is low fluid. To top up, turn ignition on and wait for pump to stop. Then top up to max level. Fluid will be above max after the car has been stood but will return to max after pump has run and stopped.
 
Even when you're under the car you'll hear the ABS pump kick in when you're bleeding. If it is being a total arse try an Ezibleed kit and flush out with that first starting with the modulator as per RAVE and working round. If no fluid is coming out then it sounds like some crud is in there somewhere. What colour is the fluid coming out? Light yellow or dark brown?
 
Mark Piercy said:
Isn't there a gauze in the fluid reservoir? Could it be starving the system if there is?
Click to expand...

That's a valid point. The apparent level is often deceptive, especially if, like mine, you need a eff off powerful torch to shine through the reservoir to see anything like a level. Keep topping up all the time when bleeding. As soon as the nut is shut off, top it up.

Don't think that's his issue though. I think he has crud in the lines somewhere.
 
Here's a thought. .
Collapsed/trapped/kinked rubber hoses?
I did mine after the rear pipes and rubber pipes handed in their notice with a sealey pressure bleeder.
Pressurises the system to 25psi and 2 litres does the whole system. I'll add not from completely empty!! Just partial system.
 
Thanks guys, will look at an ezibleed tool and see if I can find some perseverance under the spare wheel! Colour of the fluid is honey yellow. Lost a lot of fluid 3 years ago when clutch slave cylinder died and then 18months or so did bleed all the brakes through to replace fluid and then recently bleed rears after changing solid pipes. Thank you for the replies and does give incentive to try some more.
 
Don't know if this will help, but when bleeding, I find it easier to pressurize from bottom up. I use a cheap oil can with a thumb pump and pump till fluid comes out top into reservoir with no air. Works a wonder on clutches. Might work on brakes.
 
dstainton said:
Don't know if this will help, but when bleeding, I find it easier to pressurize from bottom up. I use a cheap oil can with a thumb pump and pump till fluid comes out top into reservoir with no air. Works a wonder on clutches. Might work on brakes.
Click to expand...

Not sure I'd risk a bubble going the wrong way into the modulator. It is a PITA as it is if air gets trapped in there. Be interested if anyone tries it though.
 
pressure to brakes 1.JPG
pressure to brakes 2.JPG
Hi Guys,

Well sat here with a tentative smile and not for any smutty reasons (unfortunately). So thanks for all the suggestions and encouragement.

Tonight I rigged up a little compressor set to about 10 psi and seemed to move things along nicely. Followed RAVE. The only noticeable difference being that on the offside rear caliper after two 4 sec pulses the fluid was slightly clouded but it issued forth freely and filled my little container very quickly.

Only been around the block but all lights off and nice sharp brakes. hope it is still the same tomorrow!

Next jobs...........
 
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