Amazon Wagon #2, Electric Bluegaloo

Runs better than Dana's. Don't tell Dana.

Got the calipers put back together last night. Not without a bit of drama, but wasn't too bad. I believe I slightly nicked one of the pistons but it's juuuust barely above the seal by my measurement with the pistons fully retracted. Hopefully that'll be okay.




Edit// Video!

So my initial plan was to get the brakes working temporarily with the original master/single circuit setup. That's not happening.

The first of the female tube nuts I touched last night immediately broke the brake line off. They're all super rusted upon closer inspection, so new brake lines for the whole car is at the top of the list now. I'll get started on that soon.

I tried a cheap puller for the rear drums and got nowhere, so I'm cobbling a puller of my own since the VP one is spendy. The car came with a spare set of rear drums, and one has chunks missing and cracks around the outside probably from someone hammering on it.

I pulled the studs out and separated the hub part from the drum itself.

My plan is to take a 2.5" hole saw and cut the middle out of the hub, weld a 2.5" pipe onto that, and cap it with a 1/2" thick chunk of steel with a 3/4" nut welded to it. I did buy a length of B7 tool steel threaded rod that I'll use as a jack screw and a piece of 1/2" thick flat bar to use as a handle/hammer beater. Hopefully it works well enough to pull these drums. I may give up and pay VP the money for the puller if it doesn't, but I won't be happy about it. It should wind up being an uglier version of this:



Also, when I yanked the original master cylinder off, I was able to see how the pushrod is held into the master itself, and I can repurpose those parts for the RX7 master fairly easily. I made a quick video since it's easier to show than tell.

I got a puller from Zelenda Tools way back in the 90s. It's got a T handle like that but has sliding adjustable legs that you bolt down onto the studs. Lots of penetrating oil and even a little heat and it makes short work of those difficult hubs. I believe the tool you are showing is similar to Volvos tools so it should work well.

Got the tool made up. Can't use it yet, the handle rings unbelieveably loudly at a piercing 7k Hz when I hammer it, and I'm pretty sure my wife and daughter are loading a shotgun to deal with me as we speak.

Tool looks good though.

Great success!

The tool held up, and I've got both drums off now. What a job, damn.

Wheel cylinder doesn't look like it was leaking.

Damn good shit.
Hope your neighbors don't let their dogs shit in your yard after hammering away.

dl242gt said:

Wheel cylinder doesn't look like it was leaking.

Click to expand...

Nope, and to add insult to injury, they look fairly new. Oh well, no way to know without pulling it apart.

See if the pistons move in the cylinder. It's common for them to seize if they haven't been used for a while. They may not leak until they're manipulated.

Lots of good progress this weekend. I got the RX7 master cylinder bolted in, brake lines up front mostly done, drums pulled, radiator mounted, radiator hoses on, heater line looped for now, driveshaft in, clutch master/slave swapped out, new clutch line bent, plus a bunch of other piddly stuff. I ordered some ignition stuff. The wires looked relatively recent, but one doesn't clip onto the plug well, and another pulled apart at the boot.

I did get the thing running on it's own fuel tank with the mechanical pump, so that's a win. Oh, all new fuel lines and a filter too.

Here's a few pics, nothing super coherent but we're chugging right along. Provided the budget comes together, I'm going to try and get this thing to KyleMeet next month.

I put together a video but I'll have to wait til tomorrow to upload it, the internet at my house is horrendous.

Glad to see the progress. You sure were tired there. Thanks for a enjoyable video!

I threw an ignition tuneup at the car this weekend and that really smoothed out the running. No more stumbling/missing.

I started bleeding the brakes and I'm frustrated as hell. The rears bled great, but I cannot get fluid out of the master for the fronts.

If I remove the line directly off the master, I can get it to pump fluid out. There's an 8" line to the junction block, and if I remove one of the lines off the junction block, I can get fluid to there. But after half an hour of trying, I can't get fluid to either front caliper.

I'm going to try to reverse bleed it. Maybe with the calipers and lines being completely dry it's just having a hard time creating enough of a vacuum by closing the bleeder screw at the caliper to pull fluid down. Idk, it's weird. I can definitely tell that the master is pumping air because there's a bubble in the tubing I'm using for the bleeder, and when I open the valve and the pedal is depressed, that fluid bubble in the line moves. I just can't get anything to the damn calipers, and even trying to gravity bleed for a couple hours didn't get me anything. Frustrating.

The worst part is I'm headed out of town for the week, and I'm going to have to think about this all week and not be able to touch it til Saturday.

It’s been years since I’ve worked on an Amazon, but volvo has this deal where they like to mount the MC going slightly uphill for whatever reason.
I usually lift the back of the car up on a jack to get it pointing downhill which really helps with bleeding the MC and allowing trapped air to move back into the reservoir. Tickle the pedal and it’ll usually bleed just fine, no need for a bench bleed.

Pressure bleeder or vac bleeder is also your friend. Make sure you grease those nips if you’re using a vac bleeder.

Alrighty, semi-productive weekend. It runs and drives, but not well. Got the brakes bled, I just had to do a bench bleed for that. I could've done that on the car, but decided to pull it and mess with it out of the car.

I killed one fuel pump due to a torn diaphragm. At the same time, I discovered that my brakes were dragging pretty bad, like couldn't maintain speed in 4th gear bad.

Walked home from the first drive, got the boat tank, strapped it to the roof, and drove home. By the time I got back to the house I was tired and didn't' troubleshoot the brakes much. I kinda figured it was the rears.

The next day, I went out on another test drive. Same symptoms. Made it about a mile before I killed another fuel pump, and the brakes locked. This time, they locked harder and I had to put all my strength into pushing the car backwards down a hill. I discovered this time that it was the front brakes locking up, not the rears as I thought.

I again went home, got the boat tank, and drove it the mile or so home in first and second gear. By the time I got home, the brakes were COOKING.

I jacked the front of the car up and I was not able to turn either front wheel by hand. Here's the weird part...I'm still using the brake light switch that works off line pressure, and the brake lights weren't on. I figured if there was enough pressure in the whole system to lock both front wheels, surely the brake lights would be on. But I digress.

I cracked open the bleeder on the passenger side front caliper and brake fluid shot out like 8-10". I did it again and more spewed out, and after that, both front brakes freed up, and the wheels were super easy to spin by hand. Very weird.

It's acting like bad brake hoses creating a one-way valve, but that doesn't' explain why cracking only one bleeder freed up both calipers. I might be putting too much stock in the brake lights not being on, who knows, but I figure that would be a decent indicator of pressure in the circuit.

I took it back out later that day, and while the front brakes were still dragging a bit, it never got to the point where I had to downshift to second just to keep moving. It would even roll backwards down a slight incline even after a few miles of driving. Still feels like a very slight drag, but nothing nearly as bad as it was.

Before I cracked the bleeder, the pedal felt normal, like you'd have a bit of travel before it got stiff and started slowing down, but pretty quickly it would get super hard at the top of the travel and breathing on the pedal would be enough to stop the car. It doesn't do that anymore, the pedal feels mostly normal.

I really feel like if the problem was with the pushrod setup, I could create this issue sitting in the driveway with the front wheels in the air but I can't. It only seems to happen on the road with heat. I'm going to bleed the brakes some more, my only real working theory is maybe there's air trapped somewhere in the calipers that's expanding and putting a ton of pressure on the pistons once it gets hot. Idk.

As for the fueling problem, I believe my fuel tank vent is also plugged up so after a few minutes of running on the tank, the mechanical pump starts trying to pull against vacuum and that's when the fuel stops flowing. The first fuel pump was obviously bad (torn diaphragm) but when I disassembled the spare I put on, the diaphragm looked fine. I had noticed when I took the fuel cap off that it was stuck to the filler neck and I heard suction when I pulled it off, so that's pretty clear to me. It also started pumping again once I pulled the cap off.

I may wind up having to pull the tank also, I'm getting some super fine rust/sludge past the filter.

Anyhow, here's a video from Saturday, I'll make a little update sometime this week.

I suspect that the pushrod on the master needs to be shortened. Your symptoms are classic for a piston not returning all the way and blocking the return port.

The fuel tank vent on a wagon is on the filler pipe. There's a U shaped vent pipe that attaches to a nipple on the top of the filler tube. Check that it isn't plugged or removed by the PO.

hiperfauto said:

I suspect that the pushrod on the master needs to be shortened. Your symptoms are classic for a piston not returning all the way and blocking the return port.

The fuel tank vent on a wagon is on the filler pipe. There's a U shaped vent pipe that attaches to a nipple on the top of the filler tube. Check that it isn't plugged or removed by the PO.

Click to expand...

I really don't think it's the master pushrod. I could be wrong, and I understand why you say that for sure, but it doesn't feel like the issue to me. If it was the pushrod, I should be able to make the brakes lock up with the car up on jacks and I cannot. It really seems to be heat related. The pedal feel also changes gradually over time, and I feel like if it was the pushrod the pedal feel would be consistent.

At this point, rather than screw with the Mazda master anymore I'm about to just buy an 1800 dual circuit master and try that but the master and reservoir aren't cheap and I'd hate to spend the $200 for that and still have the problem.

Furthermore, if it was the master pushrod being too long, that doesn't explain why the brake grabbing is invonsistent.

Saturday: brakes locked hard after 2 miles. Cooled off/rested overnight, car rolls easy.
Sunday AM: brakes locked hard after 2 miles. Cracked bleeder, fluid spurts out.
Sunday PM: Drove 5 miles and only noted slight brake drag.

With the return port blocked the brakes will work normally until the fluid heats up and expands. It can't get into the reservoir so it pushes the pistons out of the calipers and applies the brakes. You probably introduced some air into the system when you opened the bleeder which explains why it only dragged slightly on your last drive. Either that or you didn't get them hot enough to fully lock up.

Some drum brake master cylinders have a check valve to prevent fluid from draining back into the reservoir that will cause similar symptoms. Generally they are low mounted masters. Wilwood sells residual pressure valves for cars with masters mounted under the floorboards since modern master cylinders don't have the built in check valve. PV's are that way so the check valve must be removed when converting to front disc or they will lock the front brakes when the fluid heats up. I doubt that's your problem though.