Pressure Brake Bleeder
Discussion
I’d appreciate some advice on what I’m doing wrong!
I recently replaced the rear brake hoses and sections of rear brake pipes on my CLS, and replaced rear discs and pads at the same time. I connected up the Sealey pressure brake bleeder, and both rear nipples gave a satisfying “pffft” as air flowed out. I bled all 4 nipples until there were no bubbles, flushing a fair amount of fluid through.
The brakes felt awful at the end of that process, the pedal lacking any resistance. I reconnected the bleeder, but this time my daughter was enlisted to press the brake pedal as I opened the nipples. Both rear nipples emitted lots more air, and the rear nearside releasing what appeared to be brake fluid “foam”.
The brakes feel like every concrete now. The pressure bleeder was relegated to an automatic top-up machine. I’ve returned to home mechanics after a 30+ year absence, and this now feels like the method I last used on a few year’s old Austin Maxi was superior to using the pressure bleeder. Is the Sealey unit cra*p, or is the old way better? (I used a trigger operated vacuum bleeder years ago before buying the Sealey unit - that was even more woeful!)
I recently replaced the rear brake hoses and sections of rear brake pipes on my CLS, and replaced rear discs and pads at the same time. I connected up the Sealey pressure brake bleeder, and both rear nipples gave a satisfying “pffft” as air flowed out. I bled all 4 nipples until there were no bubbles, flushing a fair amount of fluid through.
The brakes felt awful at the end of that process, the pedal lacking any resistance. I reconnected the bleeder, but this time my daughter was enlisted to press the brake pedal as I opened the nipples. Both rear nipples emitted lots more air, and the rear nearside releasing what appeared to be brake fluid “foam”.
The brakes feel like every concrete now. The pressure bleeder was relegated to an automatic top-up machine. I’ve returned to home mechanics after a 30+ year absence, and this now feels like the method I last used on a few year’s old Austin Maxi was superior to using the pressure bleeder. Is the Sealey unit cra*p, or is the old way better? (I used a trigger operated vacuum bleeder years ago before buying the Sealey unit - that was even more woeful!)
What year is your CLS and does it have SBC? (The brake by wire system)?
If it does (have SBC) you will need to bleed it via DAS/Xentry system using the bleed process, with a pressure bleeder and will do about 1-2 Litres of brake fluid during the process.
On cars with SBC the only physical connection between pedal is through the front brakes (unassisted servo), so may find it difficult to bleed rears without going through the complete DAS/Xentry bleed procedure.
If not, just sounds like you just need to keep bleeding the air out the pipes. It can take a while sometimes, especially if you're doing it the manual way, or at some stage for some reason the reservoir has run dry when using the pressure bleeder? Might also be worth checking that all the connections are tight, there are no kinks in the lines (rigid & flexi) and air isn't entering at any connections newly made (Flairs).
Nothing has changed over the years, just make sure the nipples are only open when the brake pedal is moving down and being held down, then close the nipple when the pedal is retracting to it's start position - and repeat until pedal feels solid and good.
If it does (have SBC) you will need to bleed it via DAS/Xentry system using the bleed process, with a pressure bleeder and will do about 1-2 Litres of brake fluid during the process.
On cars with SBC the only physical connection between pedal is through the front brakes (unassisted servo), so may find it difficult to bleed rears without going through the complete DAS/Xentry bleed procedure.
If not, just sounds like you just need to keep bleeding the air out the pipes. It can take a while sometimes, especially if you're doing it the manual way, or at some stage for some reason the reservoir has run dry when using the pressure bleeder? Might also be worth checking that all the connections are tight, there are no kinks in the lines (rigid & flexi) and air isn't entering at any connections newly made (Flairs).
Nothing has changed over the years, just make sure the nipples are only open when the brake pedal is moving down and being held down, then close the nipple when the pedal is retracting to it's start position - and repeat until pedal feels solid and good.
Thanks for the reply. No, it doesn’t have SBC, and it didn’t run low on new fluid.
Nothing changed between doing it with the bleeder and doing it the old fashioned way, and I checked all the new connections and they’re all fine. Perhaps I was hasty in thinking the noise and air bubbles ceasing meant all was well, but it was noticeable from the first pedal stroke how much more force was moving things through than with the bleeder.
I think I’ll just regard the pressure bleeder as an auto-feed unit and just enrol a willing volunteer, or failing that Mrs Stegel.
Nothing changed between doing it with the bleeder and doing it the old fashioned way, and I checked all the new connections and they’re all fine. Perhaps I was hasty in thinking the noise and air bubbles ceasing meant all was well, but it was noticeable from the first pedal stroke how much more force was moving things through than with the bleeder.
I think I’ll just regard the pressure bleeder as an auto-feed unit and just enrol a willing volunteer, or failing that Mrs Stegel.
Stegel said:
Sealey pressure brake bleeder
Is that one of those things that you connect to a spare wheel or similar? They're fine for moving fluid through the system but would only be wafting it through gently with tens of PSI. The brake pedal will be applying hundreds of PSI. No surprise that it is more effective at dislodging pockets of air from the system.GreenV8S said:
Is that one of those things that you connect to a spare wheel or similar? They're fine for moving fluid through the system but would only be wafting it through gently with tens of PSI. The brake pedal will be applying hundreds of PSI. No surprise that it is more effective at dislodging pockets of air from the system.
^^^^ Wot 'e said.After the service you describe, the system would have been empty of fluid and full of air. In that situation, bubbles can get trapped in a first flush, but will 'bubble' out to where they can be flushed after a wait. Overnight is best. Maybe that made the second, daughter-powered, more effetcive
But that is being too forgiving with air-powered flushing devices. I've given up on them too. Mine wasn't a Sealey, but a 'red-box' cheapo, but I'm happy to agree with you.
John
But that is being too forgiving with air-powered flushing devices. I've given up on them too. Mine wasn't a Sealey, but a 'red-box' cheapo, but I'm happy to agree with you.
John
E-bmw said:
GreenV8S said:
Is that one of those things that you connect to a spare wheel or similar? They're fine for moving fluid through the system but would only be wafting it through gently with tens of PSI. The brake pedal will be applying hundreds of PSI. No surprise that it is more effective at dislodging pockets of air from the system.
^^^^ Wot 'e said.As stated in the post above, perhaps a double go was needed to get rid of all the air, but the results mean I’ll persist with the old “traditional” way now.
Stegel said:
It’s the one with the “garden sprayer” type pump. It’s limited to 28psi but I daresay that’s all the fluid container on the master cylinder can take.
As stated in the post above, perhaps a double go was needed to get rid of all the air, but the results mean I’ll persist with the old “traditional” way now.
Sealey one was recommended to me by a friend who uses one at work for trucks and he's never had a problem. Haven't actually had to use mine yet since I bought it, although I will be soon!As stated in the post above, perhaps a double go was needed to get rid of all the air, but the results mean I’ll persist with the old “traditional” way now.
I've been using a simple syringe and a piece of tubing for years - works perfectly.
Using a piece of tubing, attach the syringe to the bleed nipple (get one of those big syringes).
Set the syringe so the end is facing downwards and the fluid will flow into the bottom pushing the plunger up.
Open the bleed nipple and pump the brakes till clear fluid flows.
It's as simple as that...the fluid won't flow back due to the resistance of the plunger. Just be careful not to pump too much fluid into the syringe!
Using a piece of tubing, attach the syringe to the bleed nipple (get one of those big syringes).
Set the syringe so the end is facing downwards and the fluid will flow into the bottom pushing the plunger up.
Open the bleed nipple and pump the brakes till clear fluid flows.
It's as simple as that...the fluid won't flow back due to the resistance of the plunger. Just be careful not to pump too much fluid into the syringe!
Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff