FJ60 brake question (ID this part), etc... (2 Viewers)

[orion]

Turning to the collective wisdom of the forum, as I can't find info on this after an exhaustive Google search, and looking around here.

1) What is this part called? 1987 FJ60, it's located below the master cylinder, brake lines run through it...has to be a proportioning valve, right? All my searches lead to FJ62 LSPV questions and info, nothing on this.

...

The reason I ask...

2) I have a "softer than I'd prefer brake pedal", even after a new master cylinder, 4Runner front calipers, brake system in overall good condition, and lots of bleeding. Looking for some input, and I'm wondering if the part mentioned above could be a factor?

The background: Bought the truck +3years ago, and other than rear drums needing adjustment...the brakes worked well.

At the time, it had new rear wheel cylinders, and soft lines up front.

Replaced the chassis-to-axle lines with longer ones after lifting it...bled the brakes...and it still worked well.

Offroading over New Years 2017, and had a soft and sinking brake pedal at the end of the day (???). Figured the master cylinder went bad, so I replaced it (bench bled it properly). No real change, felt the same. Pedal was better, but not great feeling. Just weak overall stopping power. Figured I got a bad rebuild, so I swapped it out for another (both AISIN cores), and again...no real improvement.

Decided to check the calipers, and found a frozen piston (actually one of the 4 pistons on each side)..so I decided to replace both calipers / upgrade to 4Runner calipers.

Minor improvement, but still feels like I don't have much stopping power. Pedal feels "OK", brake booster is working (if anything, the pedal is soft, not hard).

Chocked it up to just being an old truck, and with the bigger wheels and tires...just shoddy braking.

Now, I drive my wife's "new" FJ62...and while the brakes are not amazing, they are night and day more "powerful" than mine.

So, any insight?

To recap, properly bled system, new(er) wheel cylinders and 4Runner calipers, new master cylinder, lines in good condition, brake booster checks out.

What is the part above, or what else could be the culprit?

Thanks...

- Brian

 

[cruisermatt]

I think that's a residual valve for the rear drums. Could be wrong, 62's don't have them.
You might want to look at the 4Runner master cylinder to go along with the calipers.
You probably know this but rotor diameter change is what will really improve braking performance, not much you can do about that though without changing out a lot of parts.

I was pretty happy with the braking performance with T100 master, 60 booster, TLC 46mm calipers (same piston size as 4Runner), and 60 slotted rotors on 35" tires. Big tires kill braking performance.

If you can easily get your hands on some stock size wheels and tires, maybe throw them on and see how it drives?

 

[orion]

That's exactly what it is...not sure why I couldn't find the name. Thanks.

A failed or failing residual pressure valve could explain my symptoms, I think.

What's the difference in 60 and 62 master cylinders? Nothing, right...same part numbers on RockAuto.

So if you delete the LSPV on a 62, there's no residual valve. And guys do that routinely, and without issue.

All that is to say: I bet I could delete / bypass it, and the brakes would work fine. Thoughts?

Alternatively - Does the T100 master cylinder have a residual valve built in, like the 1" 80 series master cylinder people use on mini trucks (???).

- Brian

 

[60Works]

It's a proportioning valve and it's not likely to be your problem. Air in the master is. What's the time frame between changing the master and now? Bleeding the master can be difficult. It needs to be done on the bench with hoses running from the outputs back to the reservoir. Once installed, the pedal doesn't allow enough travel to clear all the air bubbles.

If you feel you have enough braking to be safe, drive it for a few days. It can clear on its own over time.

The 62 booster is an improvement over the 60, easy bolt on upgrade. It's the difference you're feeling. You must add an external check valve like the 62.

The 4 runner calipers do nothing to improve braking but give you a less solid feel to the pedal.

 

[orion]

It's a proportioning valve and it's not likely to be your problem. Air in the master is. What's the time frame between changing the master and now? Bleeding the master can be difficult. It needs to be done on the bench with hoses running from the outputs back to the reservoir. Once installed, the pedal doesn't allow enough travel to clear all the air bubbles.

If you feel you have enough braking to be safe, drive it for a few days. It can clear on its own over time...

Thanks for the input.

The master was replaced 18 months ago, and both front calipers shortly after that...many miles driven since.

I figured it was air in the master as well - However, I (properly) bench bled it before installation, and then re-bled it once maybe 6 months ago in an attempt to fix the poor braking. No change.

It's fine to drive, just needs more effort than I like to stop well (feels like there is good braking to a point, but there's none in reserve...if that makes sense).

- Brian

 

[60Works]

Near as I can tell, the 62 booster is the same as the mid 90's 4 Runner. It can be swapped without cracking a brake line. Slight bending is required. You might consider swapping your wife's booster and taking a test drive.

Tire size? Can you lock up the tires with hard braking?

 

[orion]

Tires are 34x11, installed a few months back. Issue is no worse now than with the 33s I had on there all last year.

Cannot lock the brakes. Probably the best way to describe it is a slightly soft pedal, with "OK" braking until maybe 5/10ths...but you can't stop any faster, or lock it up, no matter how much more pressure you exert.

I believe the booster is good. If you start the truck while holding the pedal down, you can feel the assist when the vacuum builds. You can also feel the pedal get stiff after turning it off, then pumping the brakes (using up the vacuum).

- Brian

 

[Dynosoar]

Adjust the rear brakes, it makes a world of difference.
Dyno

 

[Freewheel]

Check all the vacuum assist system. I had a similar issue where my clutch booster ( on the same vacuum system) had a hole in it and would bleed the vacuum whenever I hit the the clutch and the brake at the same time. When testing vacuum at idle it worked fine, because the clutch was not engaged.
Anyhow, if you have a clutch booster, definitely cap it's vacuum line and see how the brakes work.

if you don't have a clutch booster, go through the vacuum system a bit more carefully and make sure theres not some issue with your brake booster keeping vacuum when unengaged, but losing it when engaged.
(there are different stages to how the booster works, and they depend on how far the pedal deployment is..)
Listen carefully to the booster at different stages of pressure, if you hear a continuous hiss, you may have found your leak.

 

[60Works]

Totally agree with Dynosoar about checking the adjustment of your shoes.

The 60 booster isn't very strong, even if it's working properly. It was spec'd for 28" tires. 34" tires are asking for a lot more squeeze than the system was designed to provide. 4Runner booster and calipers, 60 master, and adjusted drums should be adequate for 34". Not great, adequate. One hard panic stop and the disks will warp.

 

[orion]

Thanks for the replies...

I adjusted the drum brakes not long ago (2 months?), and while there was some improvement...it was minimal. Everything is greased and moving freely back there, and I use the e-brake every time I park (so it should be auto-adjusting, as well).

I agree the tires are making things worse, but as I mentioned above...the brakes worked well prior to 18-months ago (when something happened - master cyl failed? - while off road). They have been "off" ever since that time, despite many fixes.

Each step since has been an improvement, but they are not back to "normal". It wasn't all that evident until I got some seat time in our new FJ62. After that, hopping back into the 60 made it real obvious there's something wrong.

I have checked for a crushed brake line (thought maybe I smashed one on a rock), and they all look fine.

...

Is there a consensus...the thing under the master cylinder I believe is the residual valve - Some think it's the proportioning valve. Which is it? And can I rule it out?

- Brian

 

[orion]

Quick update: Seems like maybe it was a bad or poorly rebuilt master cylinder (twice!).

I decided to throw some $$$ at the problem this weekend, just to see what happened. Bought a new (aftermarket) 1993 T100 master cylinder (1" bore) to see if there would be a change with the bigger bore and/or a "different" new M/C.

And the braking is 100% improved. No more sinking pedal. Now it just feels like an old truck on 34" tires. That is to say: It brakes "just fine", all things considered.

- Brian

 

[SteveH]

Thanks for posting your findings.

 

[boerboel313]

Turning to the collective wisdom of the forum, as I can't find info on this after an exhaustive Google search, and looking around here.

1) What is this part called? 1987 FJ60, it's located below the master cylinder, brake lines run through it...has to be a proportioning valve, right? All my searches lead to FJ62 LSPV questions and info, nothing on this.

View attachment 1735596

...

The reason I ask...

2) I have a "softer than I'd prefer brake pedal", even after a new master cylinder, 4Runner front calipers, brake system in overall good condition, and lots of bleeding. Looking for some input, and I'm wondering if the part mentioned above could be a factor?

The background: Bought the truck +3years ago, and other than rear drums needing adjustment...the brakes worked well.

At the time, it had new rear wheel cylinders, and soft lines up front.

Replaced the chassis-to-axle lines with longer ones after lifting it...bled the brakes...and it still worked well.

Offroading over New Years 2017, and had a soft and sinking brake pedal at the end of the day (???). Figured the master cylinder went bad, so I replaced it (bench bled it properly). No real change, felt the same. Pedal was better, but not great feeling. Just weak overall stopping power. Figured I got a bad rebuild, so I swapped it out for another (both AISIN cores), and again...no real improvement.

Decided to check the calipers, and found a frozen piston (actually one of the 4 pistons on each side)..so I decided to replace both calipers / upgrade to 4Runner calipers.

Minor improvement, but still feels like I don't have much stopping power. Pedal feels "OK", brake booster is working (if anything, the pedal is soft, not hard).

Chocked it up to just being an old truck, and with the bigger wheels and tires...just shoddy braking.

Now, I drive my wife's "new" FJ62...and while the brakes are not amazing, they are night and day more "powerful" than mine.

So, any insight?

To recap, properly bled system, new(er) wheel cylinders and 4Runner calipers, new master cylinder, lines in good condition, brake booster checks out.

What is the part above, or what else could be the culprit?

Thanks...

- Brian

Sorry to hijack here, looking to upgrade my brakes. You stated 4 runner calipers up front. What year 4 runners will work and for new calipers do I need to also upgrade my 15” wheels to 16’s? Thanks much. Will,now continue reading this thread.
Hope you got it figured out.

 

[boerboel313]

It's a proportioning valve and it's not likely to be your problem. Air in the master is. What's the time frame between changing the master and now? Bleeding the master can be difficult. It needs to be done on the bench with hoses running from the outputs back to the reservoir. Once installed, the pedal doesn't allow enough travel to clear all the air bubbles.

If you feel you have enough braking to be safe, drive it for a few days. It can clear on its own over time.

The 62 booster is an improvement over the 60, easy bolt on upgrade. It's the difference you're feeling. You must add an external check valve like the 62.

The 4 runner calipers do nothing to improve braking but give you a less solid feel to the pedal.

Why don’t the 4Runner calipers help with upgrading breaking performance? Not on their own with out upgrading the MC as well? Or not at all? Txs.

 

[60Works]

Why don’t the 4Runner calipers help with upgrading breaking performance? Not on their own with out upgrading the MC as well? Or not at all? Txs.

You might search for more threads on this. Look for longer ones than the 4 you just resurrected. The 4 Runner mod was all the rage for several years then people started getting wise that it didn't actually 'fix' anything other than aftermarket parts availability.

The short answer is that the OEM calipers can lock up the wheels. Even if you add more pressure, you can't brake more than locked. So, cutting up your heat shield and changing the flex lines gains you nothing and hurts resale. The weak link is the small rotor, which is only small because we go from 28" tires to 33", overload our trucks by 1,000 lbs, and drive 80 mph instead of 55. The only fix is to install a larger rotor, which can be done with FROR's Tundra mod, but is expensive and requires changing hubs, rotors, calipers, wheels, tires, and master.

Search is your friend.

 

[boerboel313]

You might search for more threads on this. Look for longer ones than the 4 you just resurrected. The 4 Runner mod was all the rage for several years then people started getting wise that it didn't actually 'fix' anything other than aftermarket parts availability.

The short answer is that the OEM calipers can lock up the wheels. Even if you add more pressure, you can't brake more than locked. So, cutting up your heat shield and changing the flex lines gains you nothing and hurts resale. The weak link is the small rotor, which is only small because we go from 28" tires to 33", overload our trucks by 1,000 lbs, and drive 80 mph instead of 55. The only fix is to install a larger rotor, which can be done with FROR's Tundra mod, but is expensive and requires changing hubs, rotors, calipers, wheels, tires, and master.

Search is your friend.

Well Ive done several searchs obviously as to the resurrection of so many threads and no one was mentioned the years used for 4 runner calipers. My truck weighs 6500 pound, stock brakes and 33”. 2: I’m never selling my Cruiser.
Im looking for the best upgrade for the Money and the ability to source the parts from a number of 90’s 4 runners or I guess now, Tundras. And yes, larger rotors will be needed as well as that’s a key component.