Unbreak my Brakes

[orttauq]

When stopped with foot on pedal I can feel it moving slowly down. If I pump them back up the peddle will again move down slowly. The peddle will stop before the floor but I have never had a brake system do this.

Truck stops OK-ish, kinda, somewhat. ABS and LSPV removed, all new fluid, system bled like 5-6 times to get all the black fluid out.

Any ideas?

 

[bloc]

When you removed the ABS and LSPV did you make certain long-nose fittings were put back into female ports that needed them?

As detailed in @jcardona1 s thread there are different types, and if you put a short fitting into a port that needs a long one, the flats or nut on the fitting will bottom out before the flare is fully engaged and it will leak. It'll feel tight, but isn't completely right.

I dealt with this on mine in one spot.. I knew it was an issue on one fitting, but I just tightened the piss out of it and the brakes worked ok but the fitting wouldn't stop leaking slightly. Eventually found a different line that had the long non-threaded tip and now no leaks, brakes work great.

 

[DARKNESS]

Sounds like a master cylinder

 

[tacosupreme]

Sounds like a master cylinder

I agree with this dude. The piston is bleeding off pressure. Is there a better solution than stock? Like a larger master cylinder from some other Toyota?

 

[orttauq]

When you removed the ABS and LSPV did you make certain long-nose fittings were put back into female ports that needed them?

It has been a few weeks since /ABS and no leaks at master... Before that it was scary how bad it was to get it to stop.

I am a HUGE fan of OEM but PO used whatever was cheapest. I will start by replacing the Master-that is easy peasy. IF that doesn't do it then on to the calipers.

Thanks

 

[bloc]

I agree with this dude. The piston is bleeding off pressure. Is there a better solution than stock? Like a larger master cylinder from some other Toyota?

Why would a larger piston be any better? It'd just require more force at the pedal for the same clamping force at the caliper. Stock MC works great when it isn't leaking.

It has been a few weeks since /ABS and no leaks at master... Before that it was scary how bad it was to get it to stop.

I am a HUGE fan of OEM but PO used whatever was cheapest. I will start by replacing the Master-that is easy peasy. IF that doesn't do it then on to the calipers.

Sounds fair.. but, leaks are more likely at other fittings. The MC uses the short fittings, so a long one will fit there without bottoming out. My issue was in one of the steel elbows further along the braking system. I put one of the short fitting lines that went from the MC to the ABS module into the steel elbow and that is where I had a leak.

Either way.. if it were a leaking line/fitting you'd see brake fluid dripping somewhere. If you aren't losing any fluid it strongly suggests master cylinder, as there is a second seal on the shaft and this often keeps the fluid within the MC bore when you release pressure. Usually if a cylinder is leaking it doesn't have the ability to push the fluid back past the seal when you release.. so the fluid will be visible on the brake and level will drop in the reservoir.

 

[DARKNESS]

You can get new guts for the MC from Toyota. Pretty easy to swap them out.

 

[orttauq]

Kit is ~$50 and NEW MC is ~$130 form Genuine OEM Toyota Parts & Accessories | OEMGenuineParts.com so with $80 diff I will just bolt in a new one.

@bloc Thanks for the info...I did take an elbow from the ABS and use it for the gap in the rear line where the LSPV was. Will crawl under and check. I am sure this issue was there before the deletes but no 100%.

Will post an update later

 

[Wayne]

I have the same issue and I'm certain the MC is leaking internally. It's probably the original one, I've never changed it. I have replaced just about everything else in the brake system within the past two years. I had to make a panic stop a few days ago and the brakes worked fine as did the ABS system, but I need to replace the MC soon.

 

[DARKNESS]

I thought mine was working fine, but I just replaced it when I did the booster and the brakes are much firmer. I bought an Advics (Aisin) master cylinder for like $75. Aisin makes the original for Toyota. When I compared the two, I couldn't see any difference on the outside.

 

[orttauq]

I thought mine was working fine, but I just replaced it when I did the booster and the brakes are much firmer. I bought an Advics (Aisin) master cylinder for like $75. Aisin makes the original for Toyota. When I compared the two, I couldn't see any difference on the outside.

Cool! Amazon has one...in 1-2 months

 

[orttauq]

Beck Arnley? Good or bad? Amazon has one in stock

 

[DARKNESS]

Rock auto

 

[jstigler]

Used to work at a family owned front end shop. Ive put many Beck arnley master cyl on and have had very few problems. Beck Arnley is what Oreillys sells and you might get a limited lifetime warranty if you buy from them and hold onto the receipt. Depending on the price difference it might be worth having the warranty. Will probably be the same quality/warranty if you go with new from any of the big aftermarket auto parts houses NAPA, Allparts etc.

 

[DARKNESS]

On Rock Auto the Advics is also the cheapest ($68) compared to $89 for Beck Arnley.

 

[bloc]

Plus, if you get something that was an OEM supplier a factory rebuild kit or parts are more likely to work if needed in the future.

 

[Squash]

Let it sit overnight and try a gravity bleed at each bleeder.
Don't ask me why, but this has worked on a couple of my cruisers when nothing else worked.
Once the brakes firm up you can bleed again at your leisure till the brakes feel like new.
I carry a 10mm wrench just for the fun of it, so I can bleed whenever I am under the truck.

 

[DARKNESS]

Fresh brake fluid makes a big difference in general.

 

[orttauq]

Thanks all, Ordered the BeckAnrley from Amazon same day delivery so I will put it in tomorrow.

@Squash can you elaborate on 'gravity' bleed? Do you mean open the bleeder at a caliper and just let the fluid run through? I would think in a few hours the reservoir would be empty.

 

[bloc]

Doesn't take few hours.. just go caliper to caliper, hook up a clear hose so you can see what is coming out, and open one bleeder. Gravity will let it flow out well enough (assuming the rest of the system is healthy). Keep an eye on reservoir level and close the bleeder while you go to top it up. Repeat on each cylinder. I can get a pint of fresh fluid into/through the system in 20 minutes this way by myself, with the truck still on all four wheels.

To turn over ALL of the fluid push your caliper pistons back into be bores with the bleeder open (to avoid pushing that old fluid back into the system), then do the above procddure.

If you have a lot of air in the system gravity may not provide enough velocity to remove all of it.. but I've had good luck.

When I did my ABS/LSPV delete I prefilled all lines before closing up and gravity bleeding worked great.