Technical Problem bleeding brakes

[chrisparr]

Hi All,

I’m having a problem bleeding the brakes in my daughter’s 1.2 pop.

She told me the fluid level warning was on but the car was breaking fine. It was no where near breaking fine and dangerous to drive. On inspection the rear wheel cylinders were leaking, so I ordered new cylinders and rebuilt both drums (already had the drums and shoes).

I’ve just attempted to flush and bleed the system. I tried to use my pressure bleeder, but it didn’t force anything through. I’d taken it up to 22psi but nothing happened (unless I’m mistaken it should take around 15 to 20 psi).

I went back to the old fashioned method with my wife on the brake peddle and bled the driver’s side rear fine. Moved onto the passenger side rear, and I can’t get fluid through. For 30 minutes we went through the up - down - loosen - tighten - up - down….. but still no fluid. Each time I loosen the bleed nipple I get a wet spirt of air, but no fluid flowing. Given that is happening it seems pressure is holding internally and there are no leaks.

Tried the pressure bleeder again, but that still didn’t work.

Any ideas?

I’ve heard people talking about priming the ABS pump using a diagnostic tool, but every time I see that people also say you don’t need to do that (manually bleeding will sort that out).

Do I just need to keep at it and eventually fluid will come out (even if it takes an age)?

 

[Mike1alike]

I’ve heard people talking about priming the ABS pump using a diagnostic tool, but every time I see that people also say you don’t need to do that (manually bleeding will sort that out).

Do I just need to keep at it and eventually fluid will come out (even if it takes an age)?

You do need a diagnostic tool because ABS doesn't open the circuit to bleed it old style.

I think you can do it without diagnostic tool if you start the engine and do the bleeding with engine running.

 

[chrisparr]

Ah, thanks. I’ll try it with the engine running…. Tomorrow that is - I’ve had enough of the cold for today

 

[jackwhoo]

Most commonly no scan tool needed for abs unit that has been used ie not brand new and totally dry. Plus abs unit should not prevent fluid flow to each wheel ignition off.

DO NOT bleed with engine running-too easy to press pedal too far .
Only press pedal max of half travel.

Lower pressure in bleeder often better , sub 10 psi

Check bleed nipple correctly made and can be blown through.

Check brake pedal fully returns up/not held partly down by brake switch.

Use pressure bleeder with pedal pressing.

Remove bleed nipple and use finger over piston hole as a one way valve.

 

[The Panda Nut]

My understanding is you can bleed ABS brakes manually, but MES and garage diagnostics bleed the system using the ABS pump. Computer software operates the ABS and you work through the system as directed by the software. I have not bled the Panda I let my garage do this but I appreciate you are stuck. I have bled our old Seat Leon with a pressure bleeder but it was a long laborious task and I was not happy with the pedal so used to get a grage to do that electronically too as a safety follow up. Remember the Panda brakes are a diagonal split circuit. Re-bleed the front opposite corner again and try again at the back after. Maybe there is someone on the MES register near you who could assist and do this the easy way. If this doesnt work you need to check pipe conections and parts replaced again.

 

[chrisparr]

Thanks for the tips so far.

Still no joy.

What I can report that I can't build up much pressure at all on the brake pedal. If I start the engine and turn it off, a few pumps does build up some pressure, but I can't say the peddle goes rock hard. After doing this and attempting to bleed it returns to not being able to build up pressure pumping the pedal.

I have tried doing it manually in combination with the pressure bleeder, but still nothing.

I've even (very cautiously) tried it with the engine running and taking the pedal to half way (no result).

There is fluid in the reservoir, but the level is not going down as I try to bleed. I'm attempting to bleed the opposite corner (passenger front) to drivers rear that I could bleed, but I'm now wondering if there's just a mass of air behind the fluid that's coming out of that one.

As before, when I open the bleed nipple there is a spirt of wet air.

Is this an issue with air in the master cylinder (note the reservoir never ran dry that I'm aware of)?

I have a scanner tool that I can pay to download software that claims to cover Fiat ABS functions. I'm tempted to do this and see if that helps - in for a penny, in for a pound

 

[jackwhoo]

Have you checked bleed nipple?
I had one once incorrectly drilled so was effectively a solid plug.

You have had a suggestion to bleed the front caliper of the circuit you having trouble with......good idea to see if fluid can be bled out on troublesomecircuit

 

[chrisparr]

Yes, the nipple is fine (like I said, air comes out when I crack it - I assume that means it's fine), and I'm bleeding opposite corners like I've seen in guides, so fluid comes out of the rear drivers side, but I get nothing but spirts of wet air from the front passenger side. Attempting to switch to the other circuit, I get nothing but spirts of wet air from the rear passenger side as well.

I haven't tried the front drivers side yet as all guides say start at the rear.

When I say 'wet air' I mean a spirt of air with spits of fluid mixed in.

 

[Mike1alike]

Try taking the bleeding nipple out completely and let gravity work. Fluid should come out.

 

[Pugglt Auld Jock]

You need to find where the air is, sorry if that sounds obvious! If it were me I'd pinch off all flex hosed with hose clamps - Google brake hose clamps, there are many types and pretty much all do the same thing, ie close off the hose they are attached to - With all hoses clamped try the brake pedal. If it feels hard then you've got fluid in the master cylinder and it's immediate piping. However if the pedal is still poor you've either got a problem with the master cylinder itself or it needs bled and you can do this by slackening tube nuts where they exit the cylinder itself and pumping the pedal 'till fluid comes out, then retightening them. If the pedal is good with all hoses clamped then start slackening the clamps one at a time and trying the pedal as you slacken each clamp. Lines which contain no air shouldn't cause a big difference in pedal feel. (the pedal will sink slightly though as the brake shoes/pads in that part of the system move slightly) When you slacken the one with air in it the pedal will be very poor, it'll leave you in no doubt. So now you can now bleed just that line without slackening any other still clamped lines. Continue doing this until all lines are bled out. As regards the ABS. Unless you've allowed the system to stand for a long time with nipples open or pipes removed - especially pipes at the master cylinder - until the reservoir runs dry, then bleeding the ABS is not usually needed to get a good pedal. Of course you're not moving fluid in the ABS module doing this but I've done this often and never had a problem with getting a good pedal. Yes, if you're renewing the system fluid then bleeding the ABS is desirable. I do wonder how many, even main dealer workshops, actually do this though? Of course there might be a master cylinder problem and, one which slowed me up for a while, was a flex hose with a collapsed internal liner - new hose sorted that. Unusual though so not very likely.

Edit. I'd advise against pinching off hoses with something like a Mole grip. Too easy to apply too much "squeeze" to the pipe and cause internal damage. You just want to pinch the pipe enough to stop flow.

 

[chrisparr]

You need to find where the air is, sorry if that sounds obvious! If it were me I'd pinch off all flex hosed with hose clamps - Google brake hose clamps, there are many types and pretty much all do the same thing, ie close off the hose they are attached to - With all hoses clamped try the brake pedal. If it feels hard then you've got fluid in the master cylinder and it's immediate piping. However if the pedal is still poor you've either got a problem with the master cylinder itself or it needs bled and you can do this by slackening tube nuts where they exit the cylinder itself and pumping the pedal 'till fluid comes out, then retightening them. If the pedal is good with all hoses clamped then start slackening the clamps one at a time and trying the pedal as you slacken each clamp. Lines which contain no air shouldn't cause a big difference in pedal feel. (the pedal will sink slightly though as the brake shoes/pads in that part of the system move slightly) When you slacken the one with air in it the pedal will be very poor, it'll leave you in no doubt. So now you can now bleed just that line without slackening any other still clamped lines. Continue doing this until all lines are bled out. As regards the ABS. Unless you've allowed the system to stand for a long time with nipples open or pipes removed - especially pipes at the master cylinder - until the reservoir runs dry, then bleeding the ABS is not usually needed to get a good pedal. Of course you're not moving fluid in the ABS module doing this but I've done this often and never had a problem with getting a good pedal. Yes, if you're renewing the system fluid then bleeding the ABS is desirable. I do wonder how many, even main dealer workshops, actually do this though? Of course there might be a master cylinder problem and, one which slowed me up for a while, was a flex hose with a collapsed internal liner - new hose sorted that. Unusual though so not very likely.

Edit. I'd advise against pinching off hoses with something like a Mole grip. Too easy to apply too much "squeeze" to the pipe and cause internal damage. You just want to pinch the pipe enough to stop flow.

Thanks for the lengthy post. I'll get some clamps and systematically work through that.

 

[Pugglt Auld Jock]

Thanks for the lengthy post. I'll get some clamps and systematically work through that.

Good luck.