Toyota RAV4 Forums banner

1 - 14 of 14 Posts

·
Premium Member
'99 RAV4.1, 3MZ-FE, E250F 4x4, Torsen Dif
Joined
·
2,163 Posts
Discussion Starter · #1 · (Edited)
Here is something to note to prevent problems bleeding the hydraulic clutch on a LHD, there is a dividing wall inside the master cylinder reservoir that comes up to just below the minimum line. Because of this, when bleeding the clutch make sure you keep the reservoir at the max line, if you let it get to the add line it will quickly drain and you'll pull air into the clutch slave cylinder and have to start all over again.
 

·
Registered
Joined
·
409 Posts
That's interesting. It might explain why I haven't been able to get rid of the yucky coloured fluid.
My brake fluid is now nice and clean looking.
 

·
Premium Member
'99 RAV4.1, 3MZ-FE, E250F 4x4, Torsen Dif
Joined
·
2,163 Posts
Discussion Starter · #3 ·
Yeah, I spent quite a while trying to figure out why I was only pulling air with my vacuum pump. I took the line off the clutch slave cylinder and there was no fluid, I then disconnected the line between the master cylinder and the slave and still nothing even though I was right at the add level. I took the screen out and looked and there it was a divider, makes sense, you wouldn't want to loose your brakes because you you had a clutch hydraulic problem.
 

·
Premium Member
'99 RAV4.1, 3MZ-FE, E250F 4x4, Torsen Dif
Joined
·
2,163 Posts
Discussion Starter · #5 · (Edited)
Yes, they are separate after the reservoir.

The clutch slave cylinder gets its brake fluid from the master cylinder reservoir on a left hand drive car only. If you look on the right side of the reservoir you will notice a 3/8" hose that runs between the two. Inside the master cylinder reservoir there is an internal divider that goes up to just below the add fluid mark on the side of the reservoir where the hose barb is. This would provide a safety that the brakes would not be completely lost if the clutch hydraulic system had a failure. However, it does make the brakes spongy if there is a lot of air there.
 

·
Registered
Joined
·
409 Posts
I don't understand, I have a clutch master cylinder and a brake master cylinder.
I recently bled both systems and only the one I was bleeding lost fluid.
 

·
Premium Member
'99 RAV4.1, 3MZ-FE, E250F 4x4, Torsen Dif
Joined
·
2,163 Posts
Discussion Starter · #7 ·
I'm assuming your RAV4.1 is a right hand drive, so it may be different. Mine is a 99 RAV4, 4x4, 5-speed, 4 door, left drive.

The master cylinder is mounted on the left side firewall, the clutch slave cylinder is mounted just to the left and under the cruise control. The slave has no dedicated reservoir, it has a 3/8" hose going to the brake master cylinder for it's fluid reservoir.
 

·
Registered
1998 Rav4, manual transmission, 2WD, JDM engine installed in 2013
Joined
·
1,209 Posts
there is a dividing wall inside the master cylinder reservoir that comes up to just below the minimum line. Because of this, when bleeding the clutch make sure you keep the reservoir at the max line, if you let it get to the add line it will quickly drain and you'll pull air into the clutch slave cylinder and have to start all over again.
Eodgator, thank you for pointing this out. I flushed my brake system and clutch system today. Your info above saved me a lot of time. Below are some photos that I hope help explain how the brake fluid system and clutch fluid system share the same reservoir, but only until the fluid goes below the "Min" line (a.k.a. "add line") on the reservoir.

Top view, with the cruise control actuator removed:

Looking down into the reservoir, with the reservoir cap off:

Photo showing one of the ports to the brake master cylinder and the port to the clutch master cylinder:


Like Eodgator posted, the partition's height is roughly to the Min line. Below the Min line, the fwd end of the reservoir holds the brake fluid. The aft end holds the clutch fluid. From the photos, I think one can sort of see how small the volume of fluid is for the clutch system once the fluid falls below the Min line. This is why Eodgator cautions folks to keep the reservoir filled to the Max line, more or less, when doing a clutch system flush or bleed. If the fluid falls below the Min line, and with one good purge of fluid through the clutch slave cylinder bleed valve, the small volume of fluid in the clutch reservoir will be gone. Then one will have introduced a massive amount of air into the clutch system.

When the fluid in the reservoir is above the Min line, the brake and clutch systems' fluids are commingled.

My Rav's brake & clutch fluid reservoir has some slimy scum coating a good deal of its inner surface. I am going to wait until one of the master or slave cylinders fails to replace the reservoir. For obvious reasons this may be sooner rather than later. Conventional wisdom is to perform a flush of the brake & clutch systems every two years to avoid this build-up of scum.
 

·
Registered
Joined
·
186 Posts
Interesting setup! Thx for the pics.

I haven’t looked at this on my Rav yet, but I’m expecting the worst. So if I do a brake flush, and want to also flush the clutch lines, how would one go about that? Is there a bleeder valve on the clutch lines somewhere?
 

·
Registered
Joined
·
150 Posts
When I did mine, I sucked the fluid out of both sides then filled with fresh fluid, then went to the respective drain and flushed from there, refilling the reservoir as needed.
 

·
Registered
1998 Rav4, manual transmission, 2WD, JDM engine installed in 2013
Joined
·
1,209 Posts
Hi BMR, the bleeder valve for the clutch system is on the clutch slave cylinder. This thread has great photos by member Techsus showing the location of the bleeder valve: www.rav4world.com/threads/can-you-i-d-this-zerk-or-bleeder-fitting-mystery.302495/

Of course, because the brake system and clutch system pretty much share the same reservoir, I now do the brake lines and the clutch lines in the same bleeding session.
 
1 - 14 of 14 Posts
Top