SL/R230: Brake Bleeding Procedures
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Junior Member
Joined: Jul 2016
Posts: 20
Likes: 1
From: Latrobe, PA
2022 GLE 450, 2003 SL500
Brake Bleeding Procedures
Can someone please explain the correct procedure for bleeding brakes on these cars? What is different than the conventional way of cracking the bleeder and having someone pump the pedal? We tried that, opened the bleeder got a burst of fluid then nothing. Thank you
Out Of Control!!
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From: unbegrenzt
2017 GLE350 4MATIC
MBWorld Fanatic!
Joined: Mar 2018
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From: Netherlands
2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
It is essential that you understand the ins and outs of SBC before you start working on it. If you PM me your personal mail adres I can send you 3 pdf's (not allowed here) about functionality and how-to's. Be forewarned that the system is under constant high pressure (you noticed).
Super Member
Joined: Sep 2018
Posts: 746
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From: Melbourne, Australia
2005 SL 500 R230
+1 on: Do your reading first before you get up close and intimate with the braking system on these cars. There are hazards. Can I ask why you're bleeding the brakes? Did you disconnect something in the hydraulic system? There is no reason for air to get in the closed system unless you did something.
If not then the go is to replace the fluid, which will also completely eliminate any air in the system. It should be changed regularly anyway.
Here's my procedure:You need a Motive power bleeder or similar design, with the euro style cap to go on the master cylinder.
If not then the go is to replace the fluid, which will also completely eliminate any air in the system. It should be changed regularly anyway.
Here's my procedure:You need a Motive power bleeder or similar design, with the euro style cap to go on the master cylinder.
- With the car off, pump the pedal 20 - 30 times to empty the accumulator
- Disconnect both battery negatives; rear first
- Choose new DOT4 fluid, (or DOT4+ if you're planning on doing track days) with a different colour to what's already there
- Syringe the fluid out of the master cylinder and discard
- Refill with new fluid
- Attach a clear tube to one of the bleeders at the the rear, then crack the bleeder
- Put 10 - 15 psi into the power bleeder and watch until the fluid changes colour in the clear line
- Repeat for the other rear wheel, then the fronts
- Do not let the reservoir run low at any stage!
- Top up the master reservoir and put the cap back on.
- When you start the car next, you'll hear the pump run, charging up the accumulator.
Last edited by Tom Manning; Dec 7, 2022 at 05:58 PM.
Super Member
Joined: Sep 2018
Posts: 746
Likes: 183
From: Melbourne, Australia
2005 SL 500 R230
I wonder how much fluid replacement is overdone though.
My fluid was previously last changed in 2015; I tested it recently at 2.5% water content. 4% water is the maximum recommended.
I changed it anyway.
My fluid was previously last changed in 2015; I tested it recently at 2.5% water content. 4% water is the maximum recommended.
I changed it anyway.
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Out Of Control!!
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2017 GLE350 4MATIC
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Junior Member
Joined: May 2021
Posts: 31
Likes: 4
From: Dallas
2005 SL65 AMG, 1987 560SL
I remember driving through the Swiss Alps with boiled brake fluid and can confirm "Chassis" understatement of being less than desirable..... Since those very scary moments I change brake fluid at least every 2 years, it is an easy job and a great piece of mind....
Member
Joined: Nov 2024
Posts: 124
Likes: 5
From: Charleston, South Carolina USA
2004 SL500 Aegean Blue Metallic
+1 on: Do your reading first before you get up close and intimate with the braking system on these cars. There are hazards. Can I ask why you're bleeding the brakes? Did you disconnect something in the hydraulic system? There is no reason for air to get in the closed system unless you did something.
If not then the go is to replace the fluid, which will also completely eliminate any air in the system. It should be changed regularly anyway.
Here's my procedure:You need a Motive power bleeder or similar design, with the euro style cap to go on the master cylinder.
If not then the go is to replace the fluid, which will also completely eliminate any air in the system. It should be changed regularly anyway.
Here's my procedure:You need a Motive power bleeder or similar design, with the euro style cap to go on the master cylinder.
- With the car off, pump the pedal 20 - 30 times to empty the accumulator
- Disconnect both battery negatives; rear first
- Choose new DOT4 fluid, (or DOT4+ if you're planning on doing track days) with a different colour to what's already there
- Syringe the fluid out of the master cylinder and discard
- Refill with new fluid
- Attach a clear tube to one of the bleeders at the the rear, then crack the bleeder
- Put 10 - 15 psi into the power bleeder and watch until the fluid changes colour in the clear line
- Repeat for the other rear wheel, then the fronts
- Do not let the reservoir run low at any stage!
- Top up the master reservoir and put the cap back on.
- When you start the car next, you'll hear the pump run, charging up the accumulator.
Is there any worry that after the procedure you explain above is done, the batteries are reconnected, and the car is "woken up," that the priming of the accumulator will suck too much brake fluid out of the reservoir and suck air into the system?
Thanks,
Robert Brooks
Super Member
Joined: Sep 2018
Posts: 746
Likes: 183
From: Melbourne, Australia
2005 SL 500 R230
Not from my experience. The fluid in the reservoir dropped a couple of mm but no more, then you top up anyway.
Each time the pump runs it's pulling fluid from the tank into the accumulator. As it loses pressure it's pushing fluid back into the tank so it's a constant minor change anyway.
Most important is to push fluid through the system one wheel at a time but never let the reservoir run dry. As mentioned earlier IIRC this procedure does not change all the fluid in the SBC unit - just the tank and lines and calipers. If you want to replace all the fluid in the entire system then the only way is to do it with STAR and follow the factory instructions.
Each time the pump runs it's pulling fluid from the tank into the accumulator. As it loses pressure it's pushing fluid back into the tank so it's a constant minor change anyway.
Most important is to push fluid through the system one wheel at a time but never let the reservoir run dry. As mentioned earlier IIRC this procedure does not change all the fluid in the SBC unit - just the tank and lines and calipers. If you want to replace all the fluid in the entire system then the only way is to do it with STAR and follow the factory instructions.
