Unknown Brake Issues
Thread Starter
Junior Member
Joined: Jul 2019
Posts: 29
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W163 - ML320 - 1999
Unknown Brake Issues
Good Afternoon Everyone,
I have a 98' ML320 that has developed brake issues and I cannot seem to narrow down any potential source of problems in the system. I took it to a mechanic who told me that my calipers and flex hoses were worn out, I replaced them all, another mechanic told me it was my brake booster, then I replaced that as well, I noticed a large leak coming from my ABS motor therefore I replaced it with the appropriate ABS motor. The only things that I have not replaced has been my master cylinder which seems fine and my lines, which show no leaks whatsoever. Currently I am in the process of re-bleeding my brakes, even though I had bleeded them before and noticed no changes.
As of now, the car has is a lit up ABS light on the dash, I have to press the pedal several times to get any braking action whatsoever and even then it is very limited and that's it. The pedal is not falling to the back and there is no hissing whilst pushing the brake pedal down.
Any help would be greatly appreciated!
I have a 98' ML320 that has developed brake issues and I cannot seem to narrow down any potential source of problems in the system. I took it to a mechanic who told me that my calipers and flex hoses were worn out, I replaced them all, another mechanic told me it was my brake booster, then I replaced that as well, I noticed a large leak coming from my ABS motor therefore I replaced it with the appropriate ABS motor. The only things that I have not replaced has been my master cylinder which seems fine and my lines, which show no leaks whatsoever. Currently I am in the process of re-bleeding my brakes, even though I had bleeded them before and noticed no changes.
As of now, the car has is a lit up ABS light on the dash, I have to press the pedal several times to get any braking action whatsoever and even then it is very limited and that's it. The pedal is not falling to the back and there is no hissing whilst pushing the brake pedal down.
Any help would be greatly appreciated!
Thread Starter
Junior Member
Joined: Jul 2019
Posts: 29
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W163 - ML320 - 1999
The problem started a month ago. I have not needed to drive out much due to everything going on. But the fluid does not seem to be leaking anymore once I got the ABS motor replaced. Fluid in the reservoir also appears to be constant.
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From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
Your post -
https://mbworld.org/forums/m-class-w...ping-stop.html
It seems you still haven't resolved the initial problem.
No mention of any scans for saved codes. Any?
Thread Starter
Junior Member
Joined: Jul 2019
Posts: 29
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W163 - ML320 - 1999
Items done to date
no. Your problem started back in mid January 2020.
Your post -
https://mbworld.org/forums/m-class-w...ping-stop.html
It seems you still haven't resolved the initial problem.
No mention of any scans for saved codes. Any?
Your post -
https://mbworld.org/forums/m-class-w...ping-stop.html
It seems you still haven't resolved the initial problem.
No mention of any scans for saved codes. Any?
UPDATE: After testing the car down the neighborhood, it seems that I require at least three pumps of the brake pedal to bring the car to a full stop. Brake fluid level has remained constant in the reservoir though....
This is what the dash is looking like. Ignore the brake light, my emergency brakes are on since the car is sitting on a small hill.
Last edited by Michael Vanegas; Jul 12, 2020 at 07:39 PM. Reason: Update
MBWorld Fanatic!
Joined: Nov 2015
Posts: 1,456
Likes: 140
From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
And what about the BLS?
Scanned for codes?
As for the pump action brakes,
In you other post, you confirmed that you bled the brakes correctly and in the correct order.
And you're 100% sure that there is no air in the system?
Scanned for codes?
As for the pump action brakes,
In you other post, you confirmed that you bled the brakes correctly and in the correct order.
And you're 100% sure that there is no air in the system?
Thread Starter
Junior Member
Joined: Jul 2019
Posts: 29
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W163 - ML320 - 1999
I have actually never heard of a BLS. I will have to bring it to a local mechanic to check that, not sure if my little OBD code reader can read that.
As for the brakes, I have bled them multiple times from the furthest caliper to the closest to the ABS. I know that air can get trapped between the ABS and master cylinder and that this is usually a bit of a hassle to deal with (which may be my case considering I removed and replaced the ABS motor entirely).
Unless there is air trapped between the ABS and the master cylinder I am pretty sure I have sufficiently bled the system. I will be "reverse-bleeding" the brakes to see if there is any fluid left in the few lines between the ABS and master.
As for the brakes, I have bled them multiple times from the furthest caliper to the closest to the ABS. I know that air can get trapped between the ABS and master cylinder and that this is usually a bit of a hassle to deal with (which may be my case considering I removed and replaced the ABS motor entirely).
Unless there is air trapped between the ABS and the master cylinder I am pretty sure I have sufficiently bled the system. I will be "reverse-bleeding" the brakes to see if there is any fluid left in the few lines between the ABS and master.
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MBWorld Fanatic!
Joined: Nov 2015
Posts: 1,456
Likes: 140
From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
I have actually never heard of a BLS. I will have to bring it to a local mechanic to check that, not sure if my little OBD code reader can read that.
As for the brakes, I have bled them multiple times from the furthest caliper to the closest to the ABS. I know that air can get trapped between the ABS and master cylinder and that this is usually a bit of a hassle to deal with (which may be my case considering I removed and replaced the ABS motor entirely).
Unless there is air trapped between the ABS and the master cylinder I am pretty sure I have sufficiently bled the system. I will be "reverse-bleeding" the brakes to see if there is any fluid left in the few lines between the ABS and master.
As for the brakes, I have bled them multiple times from the furthest caliper to the closest to the ABS. I know that air can get trapped between the ABS and master cylinder and that this is usually a bit of a hassle to deal with (which may be my case considering I removed and replaced the ABS motor entirely).
Unless there is air trapped between the ABS and the master cylinder I am pretty sure I have sufficiently bled the system. I will be "reverse-bleeding" the brakes to see if there is any fluid left in the few lines between the ABS and master.
It's inexpensive, and you can DIY. Takes less than 5min to swap out.
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Thread Starter
Junior Member
Joined: Jul 2019
Posts: 29
Likes: 1
W163 - ML320 - 1999
Wow. I went in and just removed the connector leading to the BLS and the light immediately went out! Seems like the connection might have just been lose or something! Either way I'll pick up a new one to be extra safe but thank you! My BAS/ESP light is now out! As for the bleeding, I am still waiting for my kit to arrive but that should be the last step to make the car run perfectly again! Thank you so much!
MBWorld Fanatic!
Joined: Nov 2015
Posts: 1,456
Likes: 140
From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
Wow. I went in and just removed the connector leading to the BLS and the light immediately went out! Seems like the connection might have just been lose or something! Either way I'll pick up a new one to be extra safe but thank you! My BAS/ESP light is now out! As for the bleeding, I am still waiting for my kit to arrive but that should be the last step to make the car run perfectly again! Thank you so much!
Thread Starter
Junior Member
Joined: Jul 2019
Posts: 29
Likes: 1
W163 - ML320 - 1999
Brake progress
Hey everyone!
After many bleeds later, I finally discovered what had gone wrong..... I had installed the rear calipers backwards and the bleeder screw was along the bottom instead of top. Therefore air was stuck in the lines regardless of how many times I bled it. But finally the car is fixed and yet another item has been ticked off the list!
Thank you all for the help!
After many bleeds later, I finally discovered what had gone wrong..... I had installed the rear calipers backwards and the bleeder screw was along the bottom instead of top. Therefore air was stuck in the lines regardless of how many times I bled it. But finally the car is fixed and yet another item has been ticked off the list!
Thank you all for the help!
MBWorld Fanatic!
Joined: Nov 2015
Posts: 1,456
Likes: 140
From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
Hey everyone!
After many bleeds later, I finally discovered what had gone wrong..... I had installed the rear calipers backwards and the bleeder screw was along the bottom instead of top. Therefore air was stuck in the lines regardless of how many times I bled it. But finally the car is fixed and yet another item has been ticked off the list!
Thank you all for the help!
After many bleeds later, I finally discovered what had gone wrong..... I had installed the rear calipers backwards and the bleeder screw was along the bottom instead of top. Therefore air was stuck in the lines regardless of how many times I bled it. But finally the car is fixed and yet another item has been ticked off the list!
Thank you all for the help!
Happy Driving!
