Air in ABS pump??? (1 Viewer)

[JerseyCruiser]

When I replaced some hard brake lines on my axles earlier this year I left the brake lines open and the MC went dry. I bleed the MC with clear vinyl tubing until all of the air bubbles had disappeared, now I am concerned about air in the ABS pump. I've bleed the brakes per FSM with my Mityvac several times and it still does not seem 100% Is there any way that air is in the pump, and is there a way to bleed it by cycling it other than the SST testing device (09990-00150) from Mr. T and a trip to the stealership only to hope that they will know what I'm talking about? Seems like my 80 isn't the only one with this problem.

Thanks
George

 

[unwiredadventures]

Drive over some bumps that would activate ABS. That should get the air out. Is it safe to drive?

 

[Cattledog]

In my experiance on the 80 specificly you need to have a second person pumping.

So when you go to bleed the rears and LSPV have a second person pump the brakes and hold the petal down for about 2 seconds before you open the bleeder valve. The LSPV has a sprung pistion that controls the pressure front to rear, it takes about 2 seconds for the system to push the pistion into the correct position for bleeding.

I did this last weekend using a pressure bleeder and a second person and my brake are great. They have no spongyness and can't be pumped up. I did go through about a full gallon of fluid during the bleeding...

IMO if the abs had to be cycled the FSM would state so in the bleeding process. I had no need to cycle it.

Good Luck.

 

[Ebag333]

IMO if the abs had to be cycled the FSM would state so in the bleeding process. I had no need to cycle it.

Actually, you are supposed to check the ABS every time you work on the brakes. And part of the ABS procedure is bleeding the ABS actuator.

Most of the time you can get away without it, but if air bubbles get in there then you are stuck and have to have it bled at the dealer.

 

[96r50]

It doesn't say that anywhere in my 96 FSM (both electronic and paper copies).

This topic has come up a lot recently, and I don't see where this information is coming from. On our trucks, the ABS tool is used to do a diagnostics check of the ABS actuator to make sure all three pumps/circuits are working properly. There is no mention of using it to bleed the brakes on anything I have read. The LC is supposed to be Toyota's flagship vehicle, easily repaired with a hammer and a set of pliers in the backwoods of nowhere. Why would Toyota design an ABS system that needed a special tool to bleed? There is a lot of speculating going on here and no real proof of anything.

Granted, the ABS tool does have a "Bleed" setting on it. I've attached a piece from the 2002 4Runner FSM about using the ABS tool (or Toyota handheld tester) to bleed the brakes on that truck as it has a hydraulic brake booster. Note that it has nothing to with bleeding the ABS system. It is used (in my understanding) to trigger the hydraulic brake booster to pump the brakes. Again, NOT ABS related.

I realize I'm not adding anything in the way of a solution here, but I just want to keep the facts straight. Maybe Cdan can take a look at the ABS tool at American Toyota and clarify things for us all. As far as fixing your brakes JC, I would recommend trying Cattledog's method and see if it improves anything.