Replacing the Brake Master Cylinder Transducer, V8 Vantage
Discussion
Hi,
Well on the Aston's second outing since being put back on the road this spring i got a new error message: "Emergency Brake Assist Failure".
Bugger! The brakes seemed to work OK so I carried on. It has vanished and come back again on a regular basis since then. It could be due to a low battery voltage, but it still does it having been on a CTEK for about a week.
Anyway, time to fix the car - again!
Reading around the subject it seems it could be due to a number of things, but prime suspect appears to be the Brake Master Cylinder Transducer, which screws into the bottom of the master cylinder, or perhaps the Pedal Travel Sensor, which is a cylindrical device that fits into the servo. Being a tight wad I went for the former first of all - an original Aston Martin transducer (4G433310214) is about £105.34 + VAT. I bought a Ford/Dodge replacement, which cost about £25.00 off Ebay (Ford Dodge 5140651AA 2L1Z2B674AA).
Now to replace it. First thing is to get the plug off the bottom of the transducer, which has probably not been moved in 20 years. Dose it with WD40 as you need to be able to slide the serated section down to remove the plug. Mine didn't want to move at all at first. Once I got it moving it came off quite easily (but that took up most of the time!). Having removed the plug you can then remove the transducer. I used an 8" adjustable spanner and after the initial tightness it came away quite easily. I had visions of the entire brake reservoir splilling out of the hole, so put a small plastic container underneath it. Hint: I would prep the new sensor and have it ready to fit right away rather than searching for it mid job. In the end I did lose some brake fluid as you can see in the photograph, but it wasn't much. I shall have to see whether the brakes need bleeding once I take it out on a test drive, but I expect I will have to top up the brake reservoir at the very least.
So there you go - how to replace the Brake Master Cylinder Transducer. I don't know whether its fixed the problem or whether I will be forking out for a Pedal Travel Sensor as well (about £100 from Scuderia). But I hope this will encourage others to "have a go" themselves if they get a similar problem.
Well on the Aston's second outing since being put back on the road this spring i got a new error message: "Emergency Brake Assist Failure".
Bugger! The brakes seemed to work OK so I carried on. It has vanished and come back again on a regular basis since then. It could be due to a low battery voltage, but it still does it having been on a CTEK for about a week.
Anyway, time to fix the car - again!
Reading around the subject it seems it could be due to a number of things, but prime suspect appears to be the Brake Master Cylinder Transducer, which screws into the bottom of the master cylinder, or perhaps the Pedal Travel Sensor, which is a cylindrical device that fits into the servo. Being a tight wad I went for the former first of all - an original Aston Martin transducer (4G433310214) is about £105.34 + VAT. I bought a Ford/Dodge replacement, which cost about £25.00 off Ebay (Ford Dodge 5140651AA 2L1Z2B674AA).
Now to replace it. First thing is to get the plug off the bottom of the transducer, which has probably not been moved in 20 years. Dose it with WD40 as you need to be able to slide the serated section down to remove the plug. Mine didn't want to move at all at first. Once I got it moving it came off quite easily (but that took up most of the time!). Having removed the plug you can then remove the transducer. I used an 8" adjustable spanner and after the initial tightness it came away quite easily. I had visions of the entire brake reservoir splilling out of the hole, so put a small plastic container underneath it. Hint: I would prep the new sensor and have it ready to fit right away rather than searching for it mid job. In the end I did lose some brake fluid as you can see in the photograph, but it wasn't much. I shall have to see whether the brakes need bleeding once I take it out on a test drive, but I expect I will have to top up the brake reservoir at the very least.
So there you go - how to replace the Brake Master Cylinder Transducer. I don't know whether its fixed the problem or whether I will be forking out for a Pedal Travel Sensor as well (about £100 from Scuderia). But I hope this will encourage others to "have a go" themselves if they get a similar problem.
Well, after fitting the transducer I don't have the error I had before. Its been swapped to "Traction Control Temporary Off" and "DSC Service Required". So thinking about it, perhaps the transducer I fitted isn't as compatible as I thought. So I've ordered a "proper" one from Nicholas Mee and will let you know how I get on. I checked and there are no OBD errors. Also, the battery voltage was measured at 12.5V yesterday, which is close to the borderline for replacement. Could this be the low battery voltage causing the errors? I wouldn't be surprised. What a delight AM cars are!
Have you driven it yet ? when I changed the transducer on my previous Vantage the errors didn't go away straight away. It took a couple of stop/start cycles after a drive out, then they disappeared. Low battery voltage also a candidate, all sorts of strange errors occur when the battery is low 
Thanks for the tip - no I haven't been out in it. I thought I'd replace the transducer with a "proper" one first, but that's coming so will be a day or two. I think you're probably right. It was in the body shop for a couple of weeks so the battery fell quite low. Real buggers these aren't they?
Yes ..sometimes just a low battery can give you range of errors that look expensive. Worth investing in and OBD tool like the Foxwell for double checking errors...and keeping the battery topped up
...saying that with the ABS transducer didnt have any OBD errors showing, but the dash messages cleared after a drive it sorted itself out.
...saying that with the ABS transducer didnt have any OBD errors showing, but the dash messages cleared after a drive it sorted itself out.
Edited by bogie on Wednesday 27th May 10:47
You tend to get the same error messages for wheel speed sensor or ABS transducer. Quite a few threads on here about it over the years, I think I did mine about 13 years ago based on info found on here. One of the Aston specialists had previously said to try changing the transducer as it was easy to DIY and not so expensive. Some owners were getting quotes of £2k from main dealers to diagnose and address DSC errors !
Well blow me!!
The new brake transducer arrived in the post this morning from Nicholas Mee, so I ftted it, taking care to "prime" it with brake fluid first. I wasn't expecting miracles, but all the errors have gone! I took it for 10-mile test drive and zilch - back to normal. Nice to have a digital speedo back.
So it looks like the one I fitted originally was U/S or perhaps not compatible.
Very pleased with the result. I just want to bleed the master cylinder (there is a bleed nipple on it) to take out the air that obviously got introduced.
Thanks for all your advice and help, but it looks like its fixed (or is that the kiss of death?).
Cheers, Steve
The new brake transducer arrived in the post this morning from Nicholas Mee, so I ftted it, taking care to "prime" it with brake fluid first. I wasn't expecting miracles, but all the errors have gone! I took it for 10-mile test drive and zilch - back to normal. Nice to have a digital speedo back.
So it looks like the one I fitted originally was U/S or perhaps not compatible.
Very pleased with the result. I just want to bleed the master cylinder (there is a bleed nipple on it) to take out the air that obviously got introduced.
Thanks for all your advice and help, but it looks like its fixed (or is that the kiss of death?).
Cheers, Steve
Quick update. I bled the master cylinder (there is a bleed nipple on It) and got some air out. I also went round and bled the brakes and got some more air out. So i guess I'm saying it is best to bleed the master cylinder/brakes when changing the brake pressure transducer, in case anyone was wondering!
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