Brake system upgrade
#41
Registered User
Quite often that idle fluctuation is due to the idle being too high. The ECU is designed in such a way that if the idle is above 1000 RPM, I think it is, the ECU shuts down the injectors when the brakes are pressed. They figured that if the engine is above the max RPMs when brakes are pressed, you're slowing down, and you don't need the engine pushing hard against that. Once the idle drops below the maximum, it allows the injectors to function again. If the idle is set high, the ECU will again cut off the injectors, the idle drops, it allows them on again, the ECU senses the RPMs are too high, it cuts the injectors, etc, etc.
The idle RPM should be set to 850. Use an external tach to set the idle, not a tach built into the vehicle. Once the idle is set correctly, check the timing. Make sure the timing is correct, and check the idle one last time, once the timing is set correctly.
I won't swear that this is the trouble, but it sounds like it to me. Ok, I will swear, a lot, but I am a former Marine, so it's just a bad habit I have.
Pat☺
The idle RPM should be set to 850. Use an external tach to set the idle, not a tach built into the vehicle. Once the idle is set correctly, check the timing. Make sure the timing is correct, and check the idle one last time, once the timing is set correctly.
I won't swear that this is the trouble, but it sounds like it to me. Ok, I will swear, a lot, but I am a former Marine, so it's just a bad habit I have.
Pat☺
#42
Registered User
Thread Starter
Quite often that idle fluctuation is due to the idle being too high. The ECU is designed in such a way that if the idle is above 1000 RPM, I think it is, the ECU shuts down the injectors when the brakes are pressed. They figured that if the engine is above the max RPMs when brakes are pressed, you're slowing down, and you don't need the engine pushing hard against that. Once the idle drops below the maximum, it allows the injectors to function again. If the idle is set high, the ECU will again cut off the injectors, the idle drops, it allows them on again, the ECU senses the RPMs are too high, it cuts the injectors, etc, etc.
The idle RPM should be set to 850. Use an external tach to set the idle, not a tach built into the vehicle. Once the idle is set correctly, check the timing. Make sure the timing is correct, and check the idle one last time, once the timing is set correctly.
I won't swear that this is the trouble, but it sounds like it to me. Ok, I will swear, a lot, but I am a former Marine, so it's just a bad habit I have.
Pat☺
The idle RPM should be set to 850. Use an external tach to set the idle, not a tach built into the vehicle. Once the idle is set correctly, check the timing. Make sure the timing is correct, and check the idle one last time, once the timing is set correctly.
I won't swear that this is the trouble, but it sounds like it to me. Ok, I will swear, a lot, but I am a former Marine, so it's just a bad habit I have.
Pat☺
#43
Registered User
iTrader: (8)
Join Date: May 2011
Location: Southeast Virginia
Posts: 1,517
Likes: 0
Received 353 Likes
on
219 Posts
Second gen 4Runners with the V6 have a dual diaphragm booster which will add a good bit of boost over a single diaphragm booster. Second gen 4Runners are a dime a dozen and all over every pull-your-own junkyard. I've used them as a source for brake boosters a few times and always been happy. They swap right in, just make sure to adjust the pushrod correctly.
The following users liked this post:
keycw (11-19-2020)
#44
Registered User
Thread Starter
Second gen 4Runners with the V6 have a dual diaphragm booster which will add a good bit of boost over a single diaphragm booster. Second gen 4Runners are a dime a dozen and all over every pull-your-own junkyard. I've used them as a source for brake boosters a few times and always been happy. They swap right in, just make sure to adjust the pushrod correctly.
#45
Registered User
iTrader: (8)
Join Date: May 2011
Location: Southeast Virginia
Posts: 1,517
Likes: 0
Received 353 Likes
on
219 Posts
Never had any clearance issues. Bolt on. I believe they were original equipment on our generation of trucks if they had a V6 or 22RET. I have the same setup on both my trucks.
The following 2 users liked this post by arlindsay1992:
keycw (11-19-2020),
RAD4Runner (11-22-2020)
#46
i used a t100 dual booster on my '86 4runner... there might be two different t100 boosters, slightly different diameters? https://www.roundforge.com/articles/...booster-specs/
https://www.pirate4x4.com/threads/br...grades.132252/
the big diameter boosters hit the steering column on 1st-gen pickups, so be careful there.
i had to take it back off and remove the firewall spacer :-/ so be sure and check the pushrod distance before putting the mc back on... my pushrod is barely long enough, wish i knew where to get a longer one.
while you are under the dash, be sure and check the foot pedal bracket for cracks.
i swapped the mc also, and went with the slightly bigger rear slave cylinder, ac delco was cheaper than toyota: that's the correct landcruiser replacement, see the comments... i do have the v6 rear axle.
https://www.pirate4x4.com/threads/br...grades.132252/
the big diameter boosters hit the steering column on 1st-gen pickups, so be careful there.
i had to take it back off and remove the firewall spacer :-/ so be sure and check the pushrod distance before putting the mc back on... my pushrod is barely long enough, wish i knew where to get a longer one.
while you are under the dash, be sure and check the foot pedal bracket for cracks.
i swapped the mc also, and went with the slightly bigger rear slave cylinder, ac delco was cheaper than toyota: that's the correct landcruiser replacement, see the comments... i do have the v6 rear axle.
Last edited by osv; 11-20-2020 at 12:27 PM.
#47
Registered User
Thread Starter
i used a t100 dual booster on my '86 4runner... there might be two different t100 boosters, slightly different diameters? https://www.roundforge.com/articles/...booster-specs/
https://www.pirate4x4.com/threads/br...grades.132252/
the big diameter boosters hit the steering column on 1st-gen pickups, so be careful there.
i had to take it back off and remove the firewall spacer :-/ so be sure and check the pushrod distance before putting the mc back on... my pushrod is barely long enough, wish i knew where to get a longer one.
while you are under the dash, be sure and check the foot pedal bracket for cracks.
i swapped the mc also, and went with the slightly bigger rear slave cylinder, ac delco was cheaper than toyota: https://www.amazon.com/gp/product/B000C9FXCY/
that's the correct landcruiser replacement, see the comments... i do have the v6 rear axle.
https://www.pirate4x4.com/threads/br...grades.132252/
the big diameter boosters hit the steering column on 1st-gen pickups, so be careful there.
i had to take it back off and remove the firewall spacer :-/ so be sure and check the pushrod distance before putting the mc back on... my pushrod is barely long enough, wish i knew where to get a longer one.
while you are under the dash, be sure and check the foot pedal bracket for cracks.
i swapped the mc also, and went with the slightly bigger rear slave cylinder, ac delco was cheaper than toyota: https://www.amazon.com/gp/product/B000C9FXCY/
that's the correct landcruiser replacement, see the comments... i do have the v6 rear axle.
thanks, i have already done all the other upgrades you mention and yeah aftermarket is always cheaper but, you get what you pay for. i dont see many parts store parts lasting 30 years or more.
The following users liked this post:
RAD4Runner (11-22-2020)
#48
i had a cheap clutch master fail on me, went toyota for that part.
this acdelco 1" i.d. slave cylinder is not that, it's their pro line, with a 2-year warranty, while the cheap versions of it have a 90-day warranty: https://www.rockauto.com/en/catalog/...+cylinder,1952
the toyota version is $39 at marlin, no specified warranty: https://www.marlincrawler.com/brake/...wheel-cylinder
this acdelco 1" i.d. slave cylinder is not that, it's their pro line, with a 2-year warranty, while the cheap versions of it have a 90-day warranty: https://www.rockauto.com/en/catalog/...+cylinder,1952
the toyota version is $39 at marlin, no specified warranty: https://www.marlincrawler.com/brake/...wheel-cylinder
The following users liked this post:
RAD4Runner (11-22-2020)
#49
@arlindsay1992 ,
Thanks for info on the vacuum booster.
Does it have to come with matching master cylinder?
Pretty much any second-gen or V6 1988 4Runner? I get intermittent "notch" feel on the brake only when engine is on, so I do not think it's mechanical binding. More likely something to do with the vacuum boost. It doesn't affect stopping so I;m waiting to get replacement booster ready before I take things apart.
Thanks for your service, Pat!
That same G#$$@*$d Sh&t happened on mine, too. [LOL!- I'm a former sailor, Desert Storm on USS Tripoli LPH10, the one that ran into a mine ]
When AC was on and came to a stop at freeway exit it would hunt. Lowering to proper idle fixed it in a second.
Thanks for info on the vacuum booster.
Does it have to come with matching master cylinder?
Pretty much any second-gen or V6 1988 4Runner? I get intermittent "notch" feel on the brake only when engine is on, so I do not think it's mechanical binding. More likely something to do with the vacuum boost. It doesn't affect stopping so I;m waiting to get replacement booster ready before I take things apart.
That same G#$$@*$d Sh&t happened on mine, too. [LOL!- I'm a former sailor, Desert Storm on USS Tripoli LPH10, the one that ran into a mine ]
When AC was on and came to a stop at freeway exit it would hunt. Lowering to proper idle fixed it in a second.
Last edited by RAD4Runner; 11-22-2020 at 05:33 AM.
The following users liked this post:
keycw (11-22-2020)
#50
Registered User
Thank you for YOUR service, Rad! I remember that incident. Glad you were safe wherever you were aboard the boat.
Amazing what a small, simple adjustment can accomplish, sometimes, aint it?
Have fun!
Pat☺
Amazing what a small, simple adjustment can accomplish, sometimes, aint it?
Have fun!
Pat☺
The following users liked this post:
RAD4Runner (11-22-2020)
#51
Registered User
iTrader: (8)
Join Date: May 2011
Location: Southeast Virginia
Posts: 1,517
Likes: 0
Received 353 Likes
on
219 Posts
If you have a 1" bore master cylinder already, no need to pay for another master from the junkyard, just make sure the pushrod is adjusted correctly. However, if you're planning to do this swap for the first time, buy the master and booster together at the junkyard. Often the Pick Your Part places have a separate line item for booster and master as a unit which is cheaper than the prices separately. Also, you will not need to adjust the pushrod since the booster and master were adjusted for each other at the factory. This only applies to factory Toyota parts that are original to the vehicle, of course. I've had good luck with used OEM brake parts from the junkyard, not so much with rebuilt stuff from the parts stores. The rebuilt stuff works fine when new but they usually only last a couple years before springing a leak or some other weird thing. Toyota stuff lasts decades.
The following users liked this post:
5 Fists (11-22-2020)
#52
#53
Registered User
Thread Starter
Buttoned this project up today. I decided to take some measurements on the FJ62 booster I had, and behold! It fits. Same bolt patterns. The FJ62 does use the spacer on the back, and I had that also. I had to play the guessing game with the push rod a bit because I don’t have the SST but after 2 tried I had it right. I won’t go into detail in that here, there’s lots of thread son who to adjust them. So all in all, I now have the larger V6 calipers and rotors, FJ 60 rear wheel cylinders, V6 master, and FJ62 booster. Hope this helps at least one person.
The following 2 users liked this post by keycw:
5 Fists (11-24-2020),
RAD4Runner (11-24-2020)
#54
Registered User
Great thread and i’ll refer back to you when i do mine!
one note about pushrod length i can add since i have been through this on my 67 Camaro when upgrading to discs. If brakes feel grabby or drag and get hot your pushrod adjustment is too long.
A change of .030” on the pushrod will feel significant at the brake pedal.
one note about pushrod length i can add since i have been through this on my 67 Camaro when upgrading to discs. If brakes feel grabby or drag and get hot your pushrod adjustment is too long.
A change of .030” on the pushrod will feel significant at the brake pedal.
Last edited by Melrose 4r; 11-24-2020 at 01:51 PM.
The following 2 users liked this post by Melrose 4r:
keycw (11-24-2020),
RAD4Runner (11-24-2020)
The following users liked this post:
swampedout (12-03-2020)
#56
Thanks for keeping this thread so thorough.
As far as pushrods go, thats a really good point. When installing the master, you shouldnt have to force it onto the booster. If you do, the pushrod is already pressing the brakes. If this happens, you will smoke your rotors. I saw a car on the road a couple nights ago, rotors orange with sparks flying off them. Not safe.
As far as pushrods go, thats a really good point. When installing the master, you shouldnt have to force it onto the booster. If you do, the pushrod is already pressing the brakes. If this happens, you will smoke your rotors. I saw a car on the road a couple nights ago, rotors orange with sparks flying off them. Not safe.
Thread
Thread Starter
Forum
Replies
Last Post
skoti89
86-95 Trucks & 4Runners
14
04-25-2011 04:58 PM