Spongy and poor brakes fixed (sort of) (1 Viewer)

[Land Speeder]

After replacing my Master cylinder and bleeding a half dozen more times w/o achieving a good pedal feel I finally broke down and took it to the dealer to be bled there. I'll report back if that solves it.

sorry to hear this. Which dealer? the one on Lake City? When I was there this summer i chatted with the parts guys and one tech... I didn't get a good impression of them... but then again, i'm kind of picky when it comes to my junk.

 

[EricE]

sorry to hear this. Which dealer? the one on Lake City? When I was there this summer i chatted with the parts guys and one tech... I didn't get a good impression of them... but then again, i'm kind of picky when it comes to my junk.

Heh. Yes, lake city way. I left specific instructions that they were to use the SST and bleed while activating the ABS. I'll find out when I pick it up this afternoon. $107 for the service.
My vehicle has never been to a dealer in the 10 or so years I have had it.

 

[Land Speeder]

Heh. Yes, lake city way. I left specific instructions that they were to use the SST and bleed while activating the ABS. I'll find out when I pick it up this afternoon. $107 for the service.
My vehicle has never been to a dealer in the 10 or so years I have had it.

Actually, is your junk white? Do you frequent Lake City Way? I kept seeing a white with short-bus bumper in the area... I was staying on Ravenna Ave 2 blocks behind the Spaghetti House

 

[EricE]

Actually, is your junk white? Do you frequent Lake City Way? I kept seeing a white with short-bus bumper in the area... I was staying on Ravenna Ave 2 blocks behind the Spaghetti House

See PM.

 

[EricE]

After getting the truck back from the dealership the brakes felt good but I thought they could be a little better so I bled the brakes again myself. By this time I am so good at it that I can do it in my sleep. After that the brakes feel real good. They feel very solid when they hit, not spongy at all. The problem that I set-out to solve by replacing the master cylinder was the fact that they sometimes hit in the first ½” of pedal travel and sometimes it takes 1.5-2” of pedal travel to “hit”. That is not solved but I am not inclined to work on it further. The brakes are fine the way they are and I don’t have a clue what I would do next. The master cylinder was at 200K so it was due for replacement anyway. I have to assume that they were able to get a bubble out of the system using the SST to activate the brakes that I was not able to get out with normal bleeding.

 

[Cattledog]

I am having a similar problem, I isolated it to the lSPV. After I took the boot off the lspv the bottom of the valve was slightly wet. Upon cycling the valve I notice air bubble forming on the bottom of the pin. All I can guess was the valve was allow into into the system on the upstroke of the valve. I am replacing the valve and will post if this fixes the problem.

 

[Dave 2000]

* Flushing your fluid and replacing with synthetic also helps to get that last little bit of performance from them as the synthetic fluid is more resistant to heat and will perform just a tad better

Except when it's very cold out and you need the brakes before they have warmed, untill then your brakes will hardly work at all!

Been there done that

regards

Dave

 

[landtank]

since my last response to this thread I found a bad LSPV and a rear line that was weeping from a damaged support.

The valave has been replaced and the lines are on order. I'll report back when done.

 

[Sc0-]

I have mushy brakes as well and traced it to a leaking LSPV... I have all new brake lines and will install it with an aftermarket proportioning valve sometime in the near future.

 

[billmiranda]

says start furthest caliper (Longest line?)

 

[EricE]

Is fluid pumped through the ABS actuator through normal braking? If so, where does it go next? What I am trying to determine is whether we expect air bubbles (if they get in there) will be pushed through the system and bled out through normal bleed procedures?

 

[Ebag333]

Is fluid pumped through the ABS actuator through normal braking? If so, where does it go next? What I am trying to determine is whether we expect air bubbles (if they get in there) will be pushed through the system and bled out through normal bleed procedures?

It is pushed through the ABS actuator, but the ABS actuator acts as a high point where air can get trapped and won't get pushed out with normal bleeding.

You have to activate it while bleeding to get it out. So far, only the dealership can do that.

 

[EricE]

I fixed my brakes. I had two problems.

One was my LSPV was adjusted to send more fluid/presure to the rear brakes. I set it myself but I realize now I did it wrong. To correct the problem I adjusted the LSPV to push equal fluid/presure to front and back. From there I'll fine tune. I did this by the following procedure:
I opened a bleeder valve on a rear brake and connected a tube to the bleeder valve. The tube flowed into an output cup/reservoir. I then pushed the pedal 20 times to its stop. I have speed bleeders on each wheel so none of the fluid I pushed out would flow backwards when I let up on the pedal. This produced a certain volume of fluid in the output cup.
I then did the exact same thing with a front wheel. I found that the setting of the LSPV DOES affect how much fluid is pushed out front v.s. back. (I can't explain how it does this; remember, only one bleeder was open during this procedure, front or back) Before I adjusted the LSPV I had at least an inch more of fluid coming out of the rear brakes than the front. I then adjusted the LSPV and repeated the procedure until the back brake put out the same height/volume of fluid as a front brake.

My other problem was loose wheel bearings on one front wheel. Somehow I failed to put on the end-axel snap ring when I put on new brake rotors. This caused that side to strip the bearing retaining nuts and spindle threads. I ended up replacing the spindle and nuts to fix it.

After this my brakes are hard and consistent each time I hit them; the way they are supposed to be.

 

[Cattledog]

Fixed my brakes over the last weekend too.

First when bleeding the rear brakes and the LSPV I waited two seconds for the LSPV to actuate before opening the bleeder valve. I talk awhile ago with landtank and he mentioned that to check the lspv for piston movment. Well the piston movement take about two second. I was able to remove a significant amount of air from the system this way.

Second. I replace and adjusted the lspv. My old valve was leaking from the pistion seal.

Third, I have gone to the hawk HPS brake pads. 100 series for the front and 80 series for the rear. IMO they are better than the OEM pads.

Braking is now right. The petal can not be pumped to change feel and the truck can get the ABS to kick in at 50 mph with no issue. I adjusted the LSPV to have the ABS kick in the front about two seconds before the rears. Yes I get the ABS to work on all four wheels at once. The truck stops really well almost as fast as my 2006 sienna. I think tires are the factor between them.

It's strange to drive now because the brakes work so well. I am surprised that I let the brakes be so bad for so long.

BTW I did use a pressure bleeder and foot pumping to bleed the brakes.

 

[Land Speeder]

My other problem was loose wheel bearings on one front wheel. Somehow I failed to put on the end-axel snap ring when I put on new brake rotors. This caused that side to strip the bearing retaining nuts and spindle threads. I ended up replacing the spindle and nuts to fix it.

HUH? the snap ring would not cause your bearings to become loose. the star-fangled-washer is what holds your adustment nuts in place. That snap ring is not even on the spindle... it's on the birf.

 

[EricE]

HUH? the snap ring would not cause your bearings to become loose. the star-fangled-washer is what holds your adustment nuts in place. That snap ring is not even on the spindle... it's on the birf.

Perhaps I also failed to bend the tabs on the lock washer then. I just know the nuts had backed off to allow play and when I took them off the threads were crud. I bought new nuts and tried to put them on the spindle and found the spindle threads were garbage also. Thats when I purchased a new spindle. So maybe it was two mistakes together. Either way its fixed now.

 

[FirstToy]

I did this by the following procedure:
I opened a bleeder valve on a rear brake and connected a tube to the bleeder valve. The tube flowed into an output cup/reservoir. I then pushed the pedal 20 times to its stop. I have speed bleeders on each wheel so none of the fluid I pushed out would flow backwards when I let up on the pedal. This produced a certain volume of fluid in the output cup.

I then did the exact same thing with a front wheel. I found that the setting of the LSPV DOES affect how much fluid is pushed out front v.s. back.

(I can't explain how it does this; remember, only one bleeder was open during this procedure, front or back) Before I adjusted the LSPV I had at least an inch more of fluid coming out of the rear brakes than the front.

I then adjusted the LSPV and repeated the procedure until the back brake put out the same height/volume of fluid as a front brake.

That's interesting. So did you have to adjust the LSPV up or down and by how much?

 

[Land Speeder]

That's interesting. So did you have to adjust the LSPV up or down and by how much?

As ghetto as it might seem, I've found that a small piece of angle iron that has the holes in it work the best for raising the brake rod at the axle... that way you can easily adjust it up or down and it's not permanent. The holes are larger so they can even be "micro adjusted' if need be... done this on two of my 80's and even on some friends' 80's and it's enormously easier than crawling all the way to the LSPV...

 

[EricE]

That's interesting. So did you have to adjust the LSPV up or down and by how much?

I moved the rear End of the rod (where normal adjustment happens) down toward the axle about 3/4 of an inch.

 

[FirstToy]

end of rod - as in frame end or axle end?