Rear Brake Wheel Cylinder Replacement - 1990 - Pre-1997 Toyota Corolla and Geo Prizm

Guest AtoB

Need some help...

1990 corolla sedan, 4-door, 3-speed auto...

I was going to replace my rear brake wheel cylinders today, but none of my wrenches fit onto the two 10mm bolts that hold the cylinders on. I tried open-end, box-end, and flare nut wrenches (Craftsman) but there wasn't enough clearance on the side of the bolt -- the part of the body of the brake cylinder that connects to the brake hose was in the way, so these wrenches wouldn't fit snuggly. My 10mm socket, 1/4" drive (Craftsman) fit nicely, but only without the ratchet attached. With the ratchet attached, the strut was in the way and I couldn't get the socket over the bolt.

My question is what kind of wrench can I find to fit correctly without risking stripping the bolts? Seems like a socket that is a little shorter than standard would do the trick, but what brand should I look for? I found online something called a "wrench socket" that seems like it would fit over the bolt and then can be turned with a regular wrench as one possibility. Not sure if I'm missing some obvious trick or obvious tool here.

If anyone has done this job before and can offer some advice I'd appreciate it -- thanks!

Guest AtoB

I'll answer my own question...

I was able to get a "socket cap" which is a small metal tool that fits in the square ratchet end of the socket and has a hex head on the other end to allow the socket to be turned by a regular wrench. This gave me enough clearance to turn the bolts. They didn't require much torque to loosen, but like I said, I didn't want to risk stripping them.

I actually got a 3-piece "socket cap set" which includes a socket cap for 1/4", 3/8" and 1/2" sockets. The 1/4" cap has a 3/8" hex head, so I needed a 3/8" box-end wrench also.

While I'm at it I'll mention that the brake line has a 10mm nut, which I used a flare-nut wrench on. The bleeder valve is 8mm. Also, consider changing the rubber brake lines near the drum while you're changing the wheel cylinders since you will need to bleed the brakes afterward anyway.

Re; 1990 corolla wagon dlx

(Same problem as Guest AtoB)

I have no clearance to get a wrench on the brake cylinder bolts. None!
Not even an open ended wrench will engage enough of the head to deliver the torque to break and remove.
It's an impossible situation and I desperately need to change out these brake cylinders.
Since, I also intend to remove/rebuild the rear struts, do a complete brake overhaul and new brake hoses...
...I see no other way other than to also remove the 4 bolts that hold the hub/bearing assembly to the knuckle...
...and attempt to remove or pivot the entire brake plate assembly.
I may have to unbolt the forward control arm so the assembly can pivot on the 2 wishbone bushings. (The strut will be out at this point, but after the hub bolts are untorqued)
I believe there'll be room to use a hand grinder with a thin disc to cut/grind a gap between the bolt head and the body of the cylinder...to get enough clearance for a closed-end 10mm wrench or socket.
I see no other way.
The new brake cylinders have the proper recess to provide clearance for wrench access.
I believe these are the original brake cylinders.
Has anyone else experienced this problem?
Please give feed back on my desperate solution

320 posts

Take out the four bolts... I haven't had that problem or a '90 Corolla. What about an angled open ended wrench or one of the ones with a sorta displaced head?