Resolved: Bought the wrong master cylinder assembly? (1 Viewer)

[Brandon Ryder]

I bought a master cylinder assembly from Serra Toyota when it was on sale about 2 years ago. Saved a bunch of money and knew mine would need to be replaced eventually. Was worried though as my LC is a 2000 and possibly could be built with an earlier or later Master depending on the month it was made. Input my VIN with Serra and it said it matched my LC
The one I bought was pn 47050-60042.
Not knowing what to check for specifically, I opened the package and nothing obvious looked different. I stowed it away for later.

Now it's time to do the job. I've got everything swapped and plugging in the final electrical connectors. One of the plugs doesn't match!
Old MC:

New MC

I'm not sure what this plug does. It's the one under the reservoir. It appears to possibly be a pressure sensor? Its only three wires. And it seems like it's going to a part that can be removed.

Does anyone know what this is/ does? And can the plug be adapted?
This was my biggest concern when purchasing this part ahead of time knowing it can't be returned now. And now the thing is inoperable until I get this fixed.

 

[Brandon Ryder]

Discovered that the plug is indeed a pressure sensor. There are two part numbers listed and one of them is discontinued.

In this video, at the 3:15 mark, he says this is associated with the ATRAC system. This tracks because the timmy the toolman video on the Master swap doesn't have this plug, and that was a 98 which which was pre ATRAC



I'm contemplating just swapping the sensors. I would just alternatively replug my harness but unsure if there is a difference between the pressure sensor values that the computer sees

If @cruiserpatch is on here and sees this, maybe he can clue me in to what he knows about it, because he seemed to have a custom wiring job on this sensor in the video.

 

[Malleus]

You can do either, the sensors are functionally interchangeable.

 

[2001LC]

Since, you put your VIN # in the order form online. You're protect. The issue is time. Contact Eric at Serra. Explain the situation. Make sure to mention: you learned about the sell here in ih8mud. If your new, is still in sellable condition, when back to his door. He may be able to swap out for you.

If Eric, can't. You've other options.

1) Sell the new master and get correct one.

2) Swap your old pressure sensor or buy a new sensor. I can't say for certain, it works. As I've never done this.
Make sure to replace the solid O-ring. The split hard (spacer) o-ring, can be reused, but it too is best to replaced. Also if yours has (FSM doesn't show one) the washer/gasket, those should be replaced also. If that washer/gasket is copper. You can anneal it, and reused.

Old style, with flat housing connector

Newer style, with triangular housing connector

 

[Brandon Ryder]

Since, you put your VIN # in the order form online. You're protect. The issue is time. Contact Eric at Serra. Explain the situation. Make sure to mention: you learned about the sell here in ih8mud. If you it's still in sellable condition, when back to his door. He may be able to swap out for you.

If Eric, can't. You've two option:

1) Sell the new master and get correct one.

2) Swap your old pressure sensor or buy a new sensor. I can't say for certain, it works. As I've never done this.
Make sure to replace the solid O-ring. The split hard o-ring, can be reused, but it too is replaced. Also if yours has the washer/gasket, those should be replaced also. If that washer/gasket is copper. You can anneal it, and reused.

Old style, with flat housing connector
View attachment 3806973
Newer style, with triangular housing connector
View attachment 3806975

Thank you for the part numbers with pictures. Unfortunately I'm seeing that the older sensor part number is discontinued. Perhaps this is why my MC came with the new sensor afterall? I wonder if another new one would also include this triangular sensor.

You can do either, the sensors are functionally interchangeable.

Thanks! At this point I think I'll switch the plug on the wiring harness. This should prevent me from having any leaks from removing the sensor. It has some fluid in it from factory. Likely already bench bled.

90980-11451 is the part number for the "master cylinder pressure sensor" harness plug and is also listed as a coolant temperature sensor harness on Amazon.

Thanks gentlemen. I have a plan. If for some reason this doesn't work, I'll update.

 

[Brandon Ryder]

Actually I need one more thing: does anyone have the pin- out diagram for both these sensors so I know which wire to put where?

 

[2001LC]

Actually I need one more thing: does anyone have the pin- out diagram for both these sensors so I know which wire to put where?

I don't have where I can get at.

 

[Malleus]

Actually I need one more thing: does anyone have the pin- out diagram for both these sensors so I know which wire to put where?

It's in the EWD.

 

[Brandon Ryder]

I don't have an FSM I've had trouble finding one but i know they're out there. But regardless, i found a picture of someone else's plug. I pulled my plug apart and matched it individually for now.

FYI this device accomplished the bleeding for me. It does what tech steam does but doesn't require a laptop. It's a little slow but it works. Only about 120 on Amazon

It's a cgsulit SC510 Elite. The great part is no messing with mystery Amazon cables, no emulating old windows software on your laptop. Only quirk is that it doesn't have an internal battery. You must plug it into usb power.


ETA: took a test drive and all functioned normally! Thanks for the help.

 

[Brandon Ryder]

Final thoughts for anyone dealing with this issue: the difference between the master cylinder units that I've discovered from this is that 98 and 99s will only have 3 brake line fittings and this sensor plug will not be present. 2000 and up will have 4 brake line fittings, and a pressure sensor below the reservoir. Obviously my issue is the two types of pressure sensor fittings but thankfully it seems an easy deal to swap the harness plug.


Was digging through my notes from a few years ago and found this for master cylinder part numbers:
47050-60010 year 1999 w/o stability

47050-60012 year 2000 without stability control also 2001

47050-60041 year 2000 with stability control also 1999

47050-60042 2001 w stability control

 

[Malleus]

Both the service manual and the EWD are in the Resources section.

 

[Brandon Ryder]

Found them! Thank you. Been here years and never even knew about the resources section. Thanks!

 

[Malleus]

Yeah, that section really needs to be renamed "DO NOT LOOK HERE". It'd get way more traffic that way.

 

[2001LC]

Nice!