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I'm replacing the rear brake hardware on this '78 Toronado I bought about a month ago. The car hadn't been started or driven in about 10 years. We got it started about two weeks ago, and the brake pedal was hard and barely stopped the car. I was only moving it around in my driveway, so never more than creeping along. I figured a bad power booster? Something to look into.
So today I'm redoing the back brakes, driver's side first. When I removed the brake line from the wheel cylinder, the connection was bone dry with no fluid leaking out. I pressed the pedal, and it was still stiff and would not move down. I figured that, with one line open, it should bottom out and fluid should come shooting out the end of the line, engine running or not.
The master cylinder is full of fluid, and the level hasn't changed, which I'm guessing is not a surprise given that no fluid is being moved around.
So what's the problem? I sure hope it's a bad master cylinder as I'd hate to think there's a clog in a line somewhere. I would think it would not be a broken line as I would expect to see brake fluid all over the ground under the leak point. I have not yet done anything with the passenger side, and my guess is that side will also be dry. I inspected the part of the lines I could see at the rear of the car, which means the steel lines from the cylinders to the little splitter (or whatever it's called), plus the rubber hose from the splitter to whatever it connects to under the center of the car. I haven't inspected every inch of line on the car, but the lines and hoses I have seen all look ok, including both front brake hoses. In fact, they look surprisingly ok given the age of the car.
Disconnect the line from the master cylinder and blow some air through. Make sure you stick the other end in a bottle or something so it doesn't blow brake fluid all over. The rubber hose sections should be replaced as well.
Could be almost anything, though the M/C is likely not the problem. Could be a bad liner inside the hose to the rear axle. Could be a bad combo valve. Could be a pinched or internally rusted brake line.
Disconnect the line from the master cylinder and blow some air through. Make sure you stick the other end in a bottle or something so it doesn't blow brake fluid all over.
I thought of this as well.
Originally Posted by joe_padavano
Could be almost anything, though the M/C is likely not the problem. Could be a bad liner inside the hose to the rear axle. Could be a bad combo valve. Could be a pinched or internally rusted brake line.
Didn't want to hear this! Thanks.
Where is the combo valve? Is it also called a proportioning valve, or is that something different? What is that "splitter" that I'm calling it actually called? It's at the rear of the car. The rear brake hose connects to it, and then the two steel lines going to each of the two rear wheels come off from that.
Last edited by jaunty75; March 23rd, 2017 at 03:45 PM.
Just make sure you pre-soak the connections with a good penetrant and absolutely do not use any other wrench but a proper flare nut wrench. You should be able to get those connections apart without too much trouble.
Typically bolted to the frame below the master cylinder. Follow the two lines out of the M/C. The first thing you come to is the combo valve.
What is that "splitter" that I'm calling it actually called? It's at the rear of the car. The rear brake hose connects to it, and then the two steel lines going to each of the two rear wheels come off from that.
That's just a tee fitting. Usually it is swaged into the rear axle hose assembly.
Just make sure you pre-soak the connections with a good penetrant and absolutely do not use any other wrench but a proper flare nut wrench. You should be able to get those connections apart without too much trouble.
You optimist, you...
No question on the flare nut wrench and good soaking, but I still had to resort to the Vice Grips to get the flare nut loose from the rear axle hose on my 67. The flare nut wrench just spread open and started to spin on the nut. The trick is to stop immediately to avoid damage and move to the vice grips, tightly clamped on the flats of the hex.
Just make sure you pre-soak the connections with a good penetrant and absolutely do not use any other wrench but a proper flare nut wrench. You should be able to get those connections apart without too much trouble.
Have done both, I do have flare nut wrenches, and, so far, I have not had trouble loosening brake lines on this car. Thanks, though.
Last edited by jaunty75; March 23rd, 2017 at 03:55 PM.
I'll also add that often the flare nut often rusts to the metal tube and won't spin freely, which usually results in twisting and destroying the metal tube if you force it. Since I usually am replacing the rubber hoses anyway, I'll cut the hose if necessary, pull the retaining clip, and loosen the clips on the metal line, then push the hose fitting out of the hole in the frame. Now hold the flare nut and spin the remains of the hose to loosen it. Once the hose is off the flare nut, you can usually break the flare nut loose from the metal line with no damage. I always apply a small dab of anti-sieze between the flare nut and the tube, as well as on the flare nut threads, and work the nut back and forth to spread it before reinstalling on the new hose.
Update on this. I redid the passenger side rear brake yesterday just to finish the rear brakes, and I had the same issue as the driver's side...no fluid dripping out when I disconnected the brake line.
This morning I removed the master cylinder, and it's a mess. I had noted from the beginning that the fluid levels on both sides were fine, but the fluid was not a pretty color. Instead of clear, it was dark and dirty-looking. So I sucked it all out with a turkey baster, and the bottoms of the reservoirs on both sides are covered in gunk. I'm not going to bother with this one, and I ordered a new master cylinder (ACDelco, from Amazon, probably made in China!) and a new (actually, rebuilt) vacuum booster. Everything should be here by Tuesday, and then I'll be back at it.
As far as the combination/proportioning valve, I disconnected both lines that go to the front brakes with no problem, but the fitting for the rear brakes just would not budge with a capital B. Fluid did drip out of it when i removed the front lines, so I've decided to hope for the best and leave it for now and hope that replacing the MC and the booster will solve the problem of not being able to bleed the brakes.
I've soaked that rear brake fitting with PB Blaster, but no luck so far. The other annoying thing is that the fitting for this line is not English like the rest of them. The others are all 7/16 or 3/8 or something like that, and a flare wrench of those sizes fits and works just fine. But the fitting for the rear brake line is metric, 14 mm. Why would they have some English and some metric fittings on the same device? I've encountered metric nuts and bolts a few times already on this car. The bolts that hold the gas tank straps in place are not 9/16 like I thought, but rather 15 mm. Ugh.
The negative consequence of this metric-ness is that I didn't realize it until after I had tried to loosen the nut with what I thought was the correct-size English-unit flare wrench, and I ended up rounding the bolt very slightly with the flare wrench. Double Ugh. This is why I decided to leave it alone, reattach the other lines, and hope for the best when the MC and booster are replaced.
Since the car has been sitting for 10 years, with no maintenance, I would suggest replacing all the steel brake lines. Brake lines rust from the inside out, and if you value your life, and the lives of others, this is the best way to know that your braking system is safe. In fact, I would replace every hydraulic part of the system, or at least rebuild them, if they aren't rusted badly. Bad brakes can have disastrous results when they fail. There is nothing as important as safe brakes, steering, and good tires. A bad engine or transmission will only leave you on the side of the road. Bad brakes, steering or tires, can kill you! Be safe...
Rust probably isn't a major issue in New Mexico. I know that here in Arizona it's a non-issue due to the dry desert environment.
The car is not from New Mexico. It was sold originally in Miami, Florida and lived in Florida and Georgia all its life until I bought it and had it transported here a month ago. Now those states aren't known for their salted roads in winter, but they aren't arid climates.
It may come to replacing one or more brake lines, although those I've examined closely don't look bad, and doing a complete replacement is something I'd rather not get into if I don't have to. One step at a time.
After a couple of days of periodic spraying with PB Blaster, I managed to successfully loosen that last fitting on the proportioning valve and remove it from the car. I decided to order a new valve from Inline Tube, who claims to have the exact replacement. We'll see what it looks like when it arrives. I don't know that there's anything wrong with this one, but why not put in new after 39 years. It will be good for another 39 years.
The lack of brake fluid at the rear wheels was, in fact, due to a bad rear brake hose. I disconnected the two lines coming from the t-fitting at the back of the car and tried to blow air through the brake line from the combo-valve end. No luck. I then removed the brake hose, and success. I could blow air through the line (and blow brake fluid all over the place, but I can clean that up). The hose is clogged, so it's now in the trash, and I installed a new rear brake hose today. Everything at the back end of the car is now reconnected, and bleeding (of the brakes) will occur once the front part of the brake system (MC, booster, and combo-valve) are installed.
The combo-valve, which I got from Inline Tube, arrived today, and it is now in the car. It is a nice, drop-in replacement with all connections in the right place and the right size. I don't have the lines from the master cylinder connected yet because the MC is not installed yet. That's for tomorrow.
I've inspected closely a number of the steel lines on this car, and they're really in pretty good shape. And, yes, I'm very happy that the blockage was in the easily-replaced hose and not in the difficult-to-replace steel line.
At this point I don't plan to replace any of the steel lines. I've been able to easily loosen all nuts (except that one on the back end of the combo-valve, but it did eventually loosen cleanly), and all flared ends look good. I plan to replace the front brake hoses as well as soon as I can get back to work on that end.
Have you checked the condition of the rear wheel cylinders, looking for rust at the bottom of the bores? If the car sat for 10 years, I would be very suspect of them having rust and pitting in the cylinders. You can pull back the rubber boots, and if they are clean looking, you might be OK. If not, then consider replacing or rebuilding them.
I replaced both wheel cylinders when I redid the brakes. They're so cheap at about $6 each (price I paid at Amazon for ACDelco brand) that it's almost silly not to, and it doesn't seem worth bothering to rebuild them, again because new ones are so cheap.
I replaced everything on the back brakes (cylinders, shoes, drums, adjusters, and hold-down hard hardware). In short, if it's replaceable on the back brakes, I replaced it.
Here's the left side after the job was complete. I take pictures of everything.
Last edited by jaunty75; March 30th, 2017 at 07:48 AM.
Are you missing the guide plate that mounts on the upper stud between the brake shoes and springs. In the vicinity of the green circle. Is the parking brake crossbar installed correctly?
Are you missing the guide plate that mounts on the upper stud between the brake shoes and springs. In the vicinity of the green circle.
YES! Good eye. I noticed it was missing when I took the photo and then disassembled the hardware to put it in. Of course, I also noticed it was missing when it was sitting there on the ground after I "finished" installing everything.
I didn't retake the photo, though.
Last edited by jaunty75; March 30th, 2017 at 08:24 AM.
Here's the left rear brake with the little clip thingy at the top actually in place.
Installed the new vacuum booster and master cylinder today and then successfully bled the rear brakes. Very satisfying to have a brake pedal that actually moves like it's supposed to when you step on it instead of not budging. On to the fronts over the weekend, but I won't be able to finish until next week as I've ordered new front brake hoses, and they won't be in until Monday.
It's nice to see these new, shiny parts on this old car.
Did you have to adjust the push rod from the brake booster to the master cylinder? If it is out of adjustment, it can cause a drag on your brakes, or cause too much pedal travel. The service manual will give instructions, if the rod has an adjustment.
You are doing a great job, and knowing that it is all new, will give you confidence when driving the car.
Junk
Correct. There was nothing to adjust regarding the pushrod. I didn't have to make any adjustments for the pedal height. The new booster dropped right in in place of the old one.
To continue this car's story, today was a milestone day. I can officially declare the car "back on the road" after at least a decade. Finally finished the front brakes, which are now completely renewed (rotors, pads, calipers, hoses). Same for the rear brakes, M/C, and vacuum booster. Put new gas in the new gas tank, and it fired right up. Unlike the first time I started it about three weeks ago, this time there was no gasoline leak, and the brakes worked fine. I drove the car around the block.
What I've done to the car since its arrival on my doorstep on February 25:
1. new battery and battery cables
2. change oil and filter
3. change transmission fluid and filter
4. replace stabilizer bar end links
5. new fuel pump
6. new front shock absorbers
7. totally renewed front brakes (hoses, calipers, pads, rotors)
8. totally renewed rear brakes (hose, drums, shoes, wheel cylinders, spring hardware)
9. new fuel tank, tank sending unit, and rubber fuel lines
10. new master cylinder, vacuum booster, and proportioning valve
11. new spark plugs and plug wires
Still lots to do, but the car is at least driveable. Now I can finally get it titled and registered.
March 23rd, 2017, 02:33 PM
