Master Cylinder Rebuild - DIY (6 Viewers)

[Davidpsalt]

Let me clarify - I first pulled the entire assembly which consists of the Master Cylinder, ABS ECU, Pump Motor and Actuator - oh, and the resevoir on top! When I first pulled the assembly out, I went with the Master Cylinder rebuild kit as recommended on this side - for only $47. The kit consist of a new piston that has fresh o-rings, etc. When I reinstalled, I was able to get some brake pressure after pumping the pedal the recommended 40 times - then you are supposed to turn the key to on and the pump motor is supposed to kick on and build pressure into the actuator that pressurizes the brake system. My motor would not come on. I pulled the assembly out again and bench tested the motor by using a 12 volt battery and some speaker wire to touch the contacts and the pump works fine wiht direct power. Hence, I am guessing the problem is with a sensor - maybe the resevoir fluid level sensor is not recognizing the fluid and telling the pump not to run so it wont burn out ... I just do not have the skill or patience to test the circuits out.

I decided to take it to the dealer and I asked my service writer to have the tech do some diagnostics. They then came back with "you need the whole assembly" as like transmissions, the dealer does not rebuild them the just drop in the entire unit which runs $2,400.

I got them to match an $1,800 price and they put it in and it runs fine now with no warning lights or alarm.

Hope this helps. I know this system is complicated with lots of electronics for ABS, etc. but you would think that the problem could be isolated so that if the fluid resevoir sensor is bad just put in a $100 resevoir with the built in sensor and its fixed.

Just my 2 cents.

 

[bamachem]

I have a soft pedal the 04. Looks like this is in my future!

 

[Phx99Cruiser]

skidoo (or bluecruiser) - why do you need to perform post #3 from inside?:
"Unbolt ABS ECU and move to side. Remove two master cylinder nuts on left side of pedal and two nuts on right side. Pull clip at top of pedal assembly and remove pin."

Is this necessary? I don't see what purpose that's for....

Also on post #6 where you fabricated a make-shift vise, is that necessary or what are the options?

Thinking that I'm finally going to have to tackle this

 

[bluecruiser]

skidoo (or bluecruiser) - why do you need to perform post #3 from inside?:
"Unbolt ABS ECU and move to side. Remove two master cylinder nuts on left side of pedal and two nuts on right side. Pull clip at top of pedal assembly and remove pin."

Is this necessary? I don't see what purpose that's for....

Also on post #6 where you fabricated a make-shift vise, is that necessary or what are the options?

Thinking that I'm finally going to have to tackle this

Post 3 is how you get the whole assembly out of the truck. Those bolts are through the firewall and have to come out to get the assembly out from under the hood. I didn't create any sort of vice to hold mine. Just set it on a bench but I needed someone else to hold it while removing the plunger.

 

[Phx99Cruiser]

ah, ok. I just wasn't understanding that step and the why behind it.

Thanks!

 

[fubuki]

Master Cylinder! - YouTube


Sorry, couldn't resist.

 

[LADHA]

Repair kit

I need that middle thing which comes out that has rubber and o-rings with fibre in it.

The whole things makes alot of groooo sound and from inside a whistle like sound.

I think thats the problem have to change it instead if of changing the whole master cylinder its quite expensive any body please tell me where i can this?

 

[happy the man]

plunger removal question

Post 3 is how you get the whole assembly out of the truck. Those bolts are through the firewall and have to come out to get the assembly out from under the hood. I didn't create any sort of vice to hold mine. Just set it on a bench but I needed someone else to hold it while removing the plunger.

Hey Bluecruiser... before you removed the plunger did you take off the booster pump and actuator? I'm having trouble getting the plunger out and don't have a decent vice set up either but have been wondering if removing those items makes this any easier to get the plunger out.

It sounded like skidoo did remove them before he pulled the plunger. Thanks.

 

[lizardking100]

Great write-up!

Skidoo - Was the problem with the old piston obvious ? Was the problem wear limited to the plastic seals ?

Maybe someone could post up the parts numbers for the rebuild kit. Are there different numbers for different years?

Part No. 04493-60330 is shown to fit the following:

Land Cruiser 2005.05- 8cyl 4.7L ATM

Land Cruiser 2002.08-2005.05 8cyl 4.7L ATM

Land Cruiser 1998.01-2002.08 8cyl 4.7L ATM

 

[bluecruiser]

Hey Bluecruiser... before you removed the plunger did you take off the booster pump and actuator? I'm having trouble getting the plunger out and don't have a decent vice set up either but have been wondering if removing those items makes this any easier to get the plunger out.

It sounded like skidoo did remove them before he pulled the plunger. Thanks.

Just noticed this..have to have the whole unit out to remove plunger...had to use a small nail (or something small enough for hole) to remove the clip that holds plunger in...recently helped another guy do this rebuild and it worked for fixing his booster.

 

[showbiz]

I have been reading this excellent thread and I need a complete master with pump assem for my 1998 LX470 where can I find this unit for the $1800.00 price or better ? thanks Greg

 

[CarbonCruiser]

After the complete assembly is removed from the vehicle, can the plunger then be pulled without pulling other components off i.e(booster pump and actuator)?

EDIT in answer to question above: I was able to pull the assembly, drain the fluid from the reservior and then replace the plunger without removing any additional components. Sticky pedal fixed, and pedal is not spongy anymore.

 

[uzj100]

Guys. We are hearing stories that the ABS will no longer function after a MC rebuild. This sounds like BS. Can you clarify why the ABS lights come on? And why it will go off after a while?

 

[TLC Dan]

UZJ,

While i don't understand why, i am ok with the result. My ABS light was on for a few miles and worrisome, it went off and ABS is fully functional. It works all winter long in the snow.

TLC Dan

 

[uzj100]

Thank you. I was also thinking after I wrote this that Toyota would probably not sell a kit if the ABS would no longer function after the rebuild.

Any other stories? I think it has to do with the system pressurizing.

 

[Skidoo]

Guys. We are hearing stories that the ABS will no longer function after a MC rebuild. This sounds like BS. Can you clarify why the ABS lights come on? And why it will go off after a while?

I am guessing one of the issues is not fully bleeding the system afterwards. The amount of bleeding is a lot more than rebuilding disc calipers. With caliper rebuild the air in system is at end of lines. With master cylinder rebuild, it is at beginning of system so have to push fluid out of lines and calipers to get air from master cylinder out. For the rear it takes a while before air even shows up, as fluid in long rear lines is pushed out.

 

[cboyd]

Had more than just the soft pedal issue today. Might be headed towards a new MC.

https://forum.ih8mud.com/showpost.php?p=9013595

Any wisdom to share? Anyone successfully change just the accumulator?

 

[uzj100]

Friend in hickory had to buy a new one. Got it rebuilt but could not get pressure to build.

 

[cboyd]

Friend in hickory had to buy a new one. Got it rebuilt but could not get pressure to build.

I took it over to Jay at Renaissance and he was saying pretty much the same.

 

[chukstel]

hello skidoo, please need help. i did the MC rebuild and the brajes are working ok. but these light ABS, VSC, TRAC and BRAKE lights are all on in the dashboard. drove for more than 10km and ligh still on but brakes perfect. ABS pump working as it used to be.

I checked the DTC with scanner(not factory OEM scanner) and no code came up.

please have any idea on what to do? as i am still not convinced its done well since the lights are on.

thanks