No Fluid out of Brake Bleeders and No Brake Power

Rebuild it or junkyard.

fuck anything that isn't (performance oriented) aftermarket shit causes more headaches than they're worth

unless you're a gambling man lol

 

Another option is to do the T-100 booster/ MC upgrade instead. Can source some of these parts from a junkyard or aftermarket on RockAuto

https://www.tundras.com/threads/t100-brake-booster-upgrade.86375/

 

Was looking at that and I think I'm going to pull the trigger on that. Knock two birds out with one stone sort of deal with fixing my current problem and fixing the spongy weak brakes problem. It's also a lot more cost effective than buying from Rock Auto.

Is there a specific MC I need to work with that specific booster or can I just go with an OEM one from EBay? The link to the MC on the writeup doesn't exist anymore. I'm currently getting the Centric MC I listed since they're pretty reputable from what I've read, but if I need to swap them out I'll just return it.

I might even just return the Centric MC off the bat though and buy off EBay or Junkyard. Not sure exactly what I want to do just yet but need to get the parts shipped since I now have to make some trips to and from college to fix my truck lol

 

Actually I found it https://www.ebay.com/sch/i.html?_fr...T100+95+Pickup+Truck+93-2000+4Runner&_sacat=0

 

You can get a new T100 booster at Rock Auto:

https://www.rockauto.com/en/moreinfo.php?pk=10492224&cc=1317603&pt=1884&jsn=533

And a new MC:

https://www.rockauto.com/en/moreinfo.php?pk=1624160&cc=1317603&pt=1836&jsn=554

Bon chance!

 

Nice! I think I’m going to buy the MC on RockAuto and the brake booster from the write up on EBay. It’ll give me some peace of mind that the MC won’t fail on me under hard braking. Buying a $36 MC on EBay gives me the heebie jeebies

 

Have tested integrity of boosters when installed by putting on the connector and see if holds. Doesn't sound like it was part of the problem?

 

The Brake Booster wasn’t apart of the problem, but my pedal was pretty unresponsive before I got around to bleeding the brakes and the brake booster might’ve had something to do with it. It looks like it’s rotting a bit from the inside too from probably a little fluid from the MC, but nothing serious enough to be concerned of failure.



I’m gonna keep the booster and grab a junkyard MC just in case the upgrade doesn’t work out, or just keep the MC I ordered already.

 

That looks like the seal for the pushrod with the OEM grease, not necessarily leaking brake fluid? There is a baffle inside that assists the pedal that have found really can't be inspected well without opening them up but not done that if it holds vacuum.

 

Not talking about the white grease but the rust around the push rod. Its not really the best picture but there’s rust all over it

I’ve already ordered the parts, so that brake booster and a junkyard MC will be my backup if I can’t get the T100 upgrade to work. I just need to have multiple options in the table to get the truck working since we don’t have an extra car

 

Yippie, we got braking again! I did the T100 Brake Booster/1 Inch MC Upgrade and it went very well!

However, my pedal is very stiff, like so stiff that it's very difficult to press down to even shift into different gears. I'm assuming is because I didn't install the master cylinder and brake booster gaskets. Either that, or I have a faulty part or vacuum leak. Let me know if you guys can think of any other ideas of why pedal is stiff or what I can test for, or if this is pretty normal with the upgrade.

And yes, I do see the disconnected vacuum line to the evap box as I write this post so I'll let you know if that was the issue (UPDATE: This was not the issue)

 

Sounds like you have no vaccuum.

 

Or insufficient vacuum, maybe because more vacuum is required for that booster design.

 

May be, I just did a two of booster tests and its passed them.

Vehicle off pump the brakes until hard then turn the car on, pedal drops slightly.

Vehicle on for a couple of minutes, push down on brake and shut the car off, brake assist shouldn’t let the master cylinder kick back and press the pedal back in for at least 30 seconds. Passed that one.

only thing I noticed that had a vacuum loss was when I pushed down on the check valve it hissed some, but I’m assuming that’s normal since I’m removing gasket seal from the check valve to the brake booster.

I don’t have any kinks in my brake lines and everything bled fine. I can’t imagine it being anything other than the brake booster which seems good.

braking power is the exact same as expected, just have a really firm pedal now.

I hope the insufficient vacuum isn’t the case since I don’t see a solution to that problem (let me know if there is). The OP of the original upgrade forum never stated having this issue, though the conclusion after install wasn’t well documented.

 

I do have this second brake booster from EBay that just shipped in today, maybe I’ll throw it in there and see if it’s the same result? Shouldn’t be a bad job. I have a return on this one and the one in the vehicle is from NAPA.

I think this would be last hope solution though, since I don’t think the brake booster is faulty due to the tests, unless it’s failing internally.

 

Did you shorten the shaft?

 

Nope!

Did some diving into the original thread and found a guy with the same issue as me since I’m using factory brakes. I didn’t adjust the push rod and I think my front brakes are constantly under pressure. I’ve been driving for a bit to test and my rotors are getting black, which is a big indicator of such.

Gonna grab the tools and try and fix it tonight or tomorrow and if it isn’t the problem I’ll probably take it to a shop

 

You think your front calipers are grabbing? I had similar issue on my 68 Porsche and it was the soft lines had deteriorated with the inner lumen dissecting and trapping fluid under pressure kinda like an aortic dissection. New soft lines fixed that.

 

This!

Once the factory booster was out, I measured the distance from the mating face of the booster to that cotter pin clip I didn't get a picture of earlier. In my case, the I needed to cut 1/4" at a minimum to about 1/2" at a maximum. I ended up bottoming out the clip on the new booster and cutting about 5/16" of the new booster's shaft to allow the clip thing to screw all the way down.
Before cutting:
After Cutting (I had to cut that last 1/16" of the shaft after taking this pic because it wouldn't fit):

 

It doesn’t feel like it they’re grabbing but there are a lot of indicators saying they are. I’m going to try the push rod fix and see if it makes a difference.

I did this. I didn’t realize that’s what you were talking about. There is no way for the brake booster to clip into the brake pedal without cutting that screw since it reaches too far. To my understanding the push rod adjustment is separate from that process and I have to adjust things via this video:

 

Had this happen that fist clogged the rears and now the fronts many years later on a 72 LC. To test for clogs can start a booster and lossen the next joint to see if have flow then if so retighten and continue down the line. But you said it bled fine? IIRC you had no flow before wheb vleeding but now you do with the replacement MC? If it flows freely at the front caliper and rear cylinders then it doesn't seem clogged.

IIRC there is a spec for the pushrod clearance. Is there resistance when mating the master to the can? Ir does it slip on fully without push rod contact?

 

Seems like if you get pedal drop when starting the car then the booster is working. Did you put vacuum on it to see if it holds? Can also measure the vacuum on the line to the booster.

 

Line to the booster is measuring 20 psi, so that's not the problem and should be enough to engage the booster.

Not sure how I can measure if the vacuum to the booster directly. I put the brake bleeder kit on the check valve nipple and the vacuum shot up and read 0, which makes sense. I went in the vehicle to see if the pedal stiffened up, which it did and then released the vacuum as I pushed on the pedal. I effectively did the first test of pumping the brakes by making the vacuum and just removed the intake manifold from the equation.

Anyways, I did the tests with the pedals again and I was getting the same results that showed the booster was holding vacuum, so I don't think the brake booster is the problem and it's holding vacuum. I really think it's the push rod if you read what @Dave8699 documented from posts #68 to #114 in the original documentation of the upgrade. Seems like we have identical problems and I've just ruled out any other problems.

 

Adjusted the push rod and it's definitely the culprit. It made a big difference in the firmness of the pedal. I got the brake booster pushrod adjustment tool and it was depressing the MC by about a 8th of an inch. I eyeballed an accurate measurement of the MC to the pushrod, bolted it back together and the pedal was a lot softer. I feel like I can adjust it back a tiny bit more since the pedal is still somewhat stiff, but for now I think it's fine. It isn't a hassle to shift into drive right when I start the truck anymore.