oldskewel

iTrader: (1)

Not at all (sorry). Mine is a '91 with the supposedly crappy early first-gen brakes. But they are just fine, and work exactly as brakes should work. Not that I would certify them for use on a race track, but they do their job on a street car just fine. None of this soft, 1/2 travel stuff. In previous years I have rebuilt the calipers and the master cylinder (that was done while chasing another problem, and I don't think it was really needed; very easy to do, by the way).

But by the way ... and it may be related to your problems ... my brake light came on the other day while driving. So I checked the brake fluid reservoir = a little low, drove home, added fluid, pumped the brakes a few times, .... and found that my left front brake hose is leaking!!! So I'll be replacing all 4 hoses before driving it again. '91 with ~191k miles, and I think the hoses are original.

If you're sure you've got your system bled properly and are looking for ideas, I'll say it could be a hose with a little too much flex, and maybe about to break loose. Some report a firmer pedal feel after switching to braided SS hoses, but I will not be going that route.

But I'll guess your issue is more likely to be air. I use a pressure bleeder, and there is no doubt or difficulty about getting the brakes flushed with no air left behind.

djamps

Thing is, so do mine - they do work very well. They just have less initial bite than other cars I drive. There is absolutely nothing 'wrong' with them. I can stop on a dime or even go full lock if needed. But when I drive the LS for a couple weeks then jump in my wife's SUV or especially my Z, I need to re-train my foot to avoid whiplash lol.

Suprjdmbro

So i went ahead and just bought a new master cylinder. I built my own pressure bleeder last night, and tried it out last night and again this morning, got lots of air out, but brakes still not where I want them. So the master cylinder has got to be bad. Now I'm wondering what it is on my other car

As far as the lines go, I have another set of SS lines on order, but since I have a very similar problem on the ucf20 I doubt the lines will help.

oldskewel

iTrader: (1)

It still sounds like something is wrong with your system, especially after re-reading your earlier comment on this. I would describe my '91's brakes as ... perfect for a luxury car. Absolutely nothing I would do to improve them. I know that many people want big rims, big brakes, stickers on their windows, etc., since they look cool (maybe), but the brakes, even on the earliest LS400's _should_ work perfectly unless something is wrong with the system.

I can go from my luxury sedan LS400 to my old 911 to my X5 to my wife's minivan, and their brakes are all differently designed (e.g., as you say, an SUV will be more whiplash inducing, by design), but they all work fine and don't feel soft or delayed.

BTW, on those pages from the manual ...

I have never bled my ABS directly, as shown there. I checked the manual for my '91, and looked at the ABS block and confirmed that there is no ABS bleeding possible on my car by that method. If there were a known serious air-in-ABS problem, you could loosen some lines to get a similar result, but there is no bleed plug for me.

I think the OP's original method of dirt-road braking to ensure that the ABS activates would mix fluid in the ABS block (that would normally be isolated from the rest of the system during the normal bleeding procedure) with the clean, new, air-free fluid in the rest of the system. And if followed up with re-bleeding the system using regular bleeding methods, that would go a long way to bleeding and flushing the fluid in the ABS actuator. So if his ABS actuator does not have a bleed plug, then what he did is probably as good as he could reasonably get, and more than I have ever done.

OP, have you tried bleeding the master cylinder? That procedure is separate from bleeding the rest of the brake system. Very simple to do that too. You would generally never need to do it, but if the reservoir were to ever run dry (as for example during a brake bleeding when you accidentally let it empty), the MC would need to be bled.

timmy0tool

iTrader: (7)

yep i also experience this lack of initial bite when first pressed, and i had the same concerns as to why. after reading a bit i came to the conclusion that it's just how the car behaves (not ideal but it's not a problem either). i too could barely put my foot under the pedal during full braking, but the car can stop well even with wide 19s on 275 tires.

lol on the whiplash comment after driving the LS for so long then jumping into another car! i feel ya on that one.

djamps

I do plan on flushing/bleeding the whole brake system maybe even SS lines as the 200k stock ones are surely soft... but like I said I did alot of research on this and based on my findings it's super low on my priority list. I'll consider myself lucky if the car outlasts brake job I did 5k miles ago lol.

Suprjdmbro

Yes I have bled the MC, its about the first thing I tried. The new MC should be here tomorrow AM, hopefully it solves all the issues for the UCF10.

dicer

I'm not a fan of pressure bleeding, can be messy if the cap leaks, and ruin paint. Always wash off the brake fluid that gets on paint, under hood or other wise.

Suprjdmbro

Alright so it seems my issues have been solved, I replaced the MC on the UCF10, had almost no change, so then I rebled the trac system and the ABS and now it seems to be all good. I did not drive it between trac and abs bleeding so I am unsure which one fixed my problem, or if I just forced a lot of air that was somehow trapped in the MC through the whole system, and had to rebleed everything. On the UCF20, with SS lines, drilled and slotted rotors, aggressive pads and a new MC as well, I bled the ABS (no trac) and wow what a difference, the brakes are incredible.

I have yet to actually roadtest the UCF10, I only drove it out of the garage and to where I park it as I decided to test drive the 20 around town instead, but none the less they still felt great on the 10 as well.

dicer

So how did you bleed them? I thought that to especially bleed the trac you need to run the motor.
And same for abs on the ucf10's anyway.

Suprjdmbro

For Abs i built a pressure bleeder, good thing I had a spare cap laying around that fit the master cylinders!
For trac I found a way on the SC subforum that involved jacking the rear of the car up and giving the car throttle, essentially "spinning the wheels" thus activating trac, and opened the bleeder valve per the FSM that i found deep on clublexus. The trac system has two bleeder valves, one for the accumulator and one for the acuator.

https://www.clublexus.com/forums/per...n-control.html
This is what gave me the idea, and then I found another thread somewhere that contained a FSM screenshot...which I cannot seem to locate now, but it is out there somewhere!

Suprjdmbro

P.S. I also bled all the calipers with the key in the ignition. I received mixed views on if this actually works or not but to be on the safe side, I decided it could not hurt and did it that way. The ign on method is supposed to run the ABS pump, ensuring all the air gets worked out of the system.
It may also worth mentioning for anyone else who has any annoying brake issues, I rebled the master cylinder after i bench bed it and got alot of air out, then rebled all of the calipers...again. (with the key on)

dicer

I most always do the vacuum bleed deal, I had a pressure bleeder make a huge mess in the past, I don't like them. I got electrical connectors to power stuff up for bleeding I haven't had to do it yet.

oldskewel

iTrader: (1)

Nice work getting it all fixed. Do you think it could just have been that all it needed was a really really thorough bleeding like you gave it? Any idea how air got into the system like that in the first place?

I pressure bled mine the other day when replacing all the brake hoses. For my cars, where I don't have a spare cap (I have done that where I buy a new MC cap and use the old one to make a pressure adapter), is I go to Home Depot and buy a rubber end cap that is meant to cap the end of a low pressure waste line in your house. Various sizes are available. I then use a steel hose clamp to go around it and clamp it onto the MC reservoir. The pressure hose comes in through a hole I drilled in the top (tight fitting around the soft vinyl hose).

BTW, I had one hose leaking, so I replaced all 4 at 25 years old and 191k miles. I cut apart the bad hose at the failure point and confirmed that these hoses have a rubber inner hose, then a woven fabric layer, then a rubber outer cover. In my case, at the failure point, the inner hose had torn lengthwise (longitudinally), and then not surprisingly the outer rubber cover had torn as well. Glad I replaced all 4. These will now definitely out-live the car.

Suprjdmbro

I'm pretty certain the old M/C was bad, as it did not consistently hold brake pedal pressure. I'm not sure how air got in there, I've only had the car for a short time, and I have no history of the car.

However:::::I have a new issue with the 93 now, the rear calipers keep seizing! After I drive the car for about 10-15 minutes and the fluid gets hot the rear calipers seize. I've replaced the calipers, and the rear lines. I am now thinking that the master cylinder I bought is bad. If I crack open the line on the MC for the rear brakes (fitting on the front on the MC) the pressure is relieved, and the calipers open back up. The braking issues with this car have been such a pain in the ***! I dont think there's any air in the lines as I've bled the lines soo many times and bled the master on and off of the car, and the calipers still drag. Slide pins are nice and lubed, calipers are good, hoses good. I think the only other option is my new MC is bad