Soft/Hard brake pedal (1 Viewer)

[OffRoadScott]

I tried the search feature for the issues I am having but couldn't really find anything.

This morning on the way to work I was getting a soft-pedal the pedal also would go to the floor, after two pumps of the pedal it would be hard but not fully apply the brakes. When it did brake the pedal/
calipers acted very sensitive.

I know my right front caliper has had some issues with the pistons and I do plan on replacing both shortly.

But what is really weird to me is when I turn the LC off it is like the brake pedal is snapping back against my foot. Has anyone ever had an issue like this?

Could the soft pedal be a failing master cylinder/booster? But what about the snapping back pedal?

 

[flintknapper]

You may have a number of issues. A 'soft/spongy' pedal feel is generally air in the system. This can be made worse by old rubber lines (your soft lines)...as they tend to bulge under the pressure.

The feeling of a harder/rebounding pedal with the engine off is normal....since you don't have the brake booster working for you.

A failing brake booster (with engine running) will produce a harder feeling pedal (pedal effort) but will not effect the low pedal position (it will still be present) if you have air in the system.

Of course, calipers that leak or are otherwise compromised will result in poor brake performance as well.

 

[OffRoadScott]

You may have a number of issues. A 'soft/spongy' pedal feel is generally air in the system. This can be made worse by old rubber lines (your soft lines)...as they tend to bulge under the pressure.

The feeling of a harder/rebounding pedal with the engine off is normal....since you don't have the brake booster working for you.

A failing brake booster (with engine running) will produce a harder feeling pedal (pedal effort) but will not effect the low pedal position (it will still be present) if you have air in the system.

Of course, calipers that leak or are otherwise compromised will result in poor brake performance as well.

I guess it is a good thing I am going to be switching out the brake lines for longer ones that I have had.

The pedal rebounding is more like a snapback, not a gradual rebound. I have never felt that in any car/vehicle I have ever owned.

 

[Bear80]

The pedal rebounding is more like a snapback, not a gradual rebound. I have never felt that in any car/vehicle I have ever owned.

Sounds like the booster. Mine started failing like that. The mushy brakes are a separate issue with the fluid/air/cylinders.

 

[flintknapper]

I guess it is a good thing I am going to be switching out the brake lines for longer ones that I have had.

The pedal rebounding is more like a snapback, not a gradual rebound. I have never felt that in any car/vehicle I have ever owned.

I've had my 80 series almost 19 yrs. now and over the years have bled the system numerous times. I have found it to be the single most difficult system I have ever worked on...in terms of getting all the air out of it. This is mostly owing to the ABS system and LSPV. I usually gravity bleed for a period of time before pressure bleeding. Invariably have to activate the ABS and then re-bleed.

Yes, the stock set up can provide good braking. Getting there....has always been tedious (for me).

I'm not suggesting anyone modify their system in any way, but I am strongly considering deleting the ABS and LSPV on mine, since mine is only driven on the ranch or for short trips into town these days (I am retired).

 

[shocktower]

I guess it is a good thing I am going to be switching out the brake lines for longer ones that I have had.

The pedal rebounding is more like a snapback, not a gradual rebound. I have never felt that in any car/vehicle I have ever owned.

Make sure you do all 7 brake lines

 

[shocktower]

I've had my 80 series almost 19 yrs. now and over the years have bled the system numerous times. I have found it to be the single most difficult system I have ever worked on...in terms of getting all the air out of it. This is mostly owing to the ABS system and LSPV. I usually gravity bleed for a period of time before pressure bleeding. Invariably have to activate the ABS and then re-bleed.

Yes, the stock set up can provide good braking. Getting there....has always been tedious (for me).

I'm not suggesting anyone modify their system in any way, but I am strongly considering deleting the ABS and LSPV on mine, since mine is only driven on the ranch or for short trips into town these days (I am retired).

The best way to bleed this system and not deleting stuff is a pressure bleeder I have done dozens and never had problems when I use a pressure bleeder...............

 

[flintknapper]

The best way to bleed this system and not deleting stuff is a pressure bleeder I have done dozens and never had problems when I use a pressure bleeder...............

I've used a 'Motive' pressure bleeder for the last 12 yrs. or so. I consider it the easiest way to get a continual flow of fluid, but it has not been my experience that it changes anything related to getting all the air out of the Anti-Lock system or the LSPV. It makes a fluid exchange much faster than other techniques and doesn't require a helper, but is nothing magical otherwise.

 

[Bear80]

Ditto on the power bleeder for only being good for a fluid change. I have to pump mine to 25psi+ to get any reasonable flow. I traced a piece of 1/2" wood to match the plastic cap so it cannot flex and burst off the fluid reservoir when tightening the chain. Flintknapper's cap is pretty sweet though.

Toyota truck brakes are a pain to get all the air out, regardless of ABS. I've experienced this with my '86 4x4 and on a '87 4Runner. On my Land Cruiser I finally used this Phoenix tool and got solid results. I will admit the reverse pressure bleeding was messy but it got the job done. Contrary to any negative reviews, I would recommend fully understanding the instructions before using it and the plastic version is robust enough if you have any amount of mechanical dexterity.

 

[OffRoadScott]

Ditto on the power bleeder for only being good for a fluid change. I have to pump mine to 25psi+ to get any reasonable flow. I traced a piece of 1/2" wood to match the plastic cap so it cannot flex and burst off the fluid reservoir when tightening the chain. Flintknapper's cap is pretty sweet though.

Toyota truck brakes are a pain to get all the air out, regardless of ABS. I've experienced this with my '86 4x4 and on a '87 4Runner. On my Land Cruiser I finally used this Phoenix tool and got solid results. I will admit the reverse pressure bleeding was messy but it got the job done. Contrary to any negative reviews, I would recommend fully understanding the instructions before using it and the plastic version is robust enough if you have any amount of mechanical dexterity.

After work today I climbed underneath the LC, it looks like the hose from the frame to the axle is the culprit. Very little seepage where it attaches at the axle. The wife is heading out of town this weekend, so I'll have her car. I am going to do the ABS and the LSPV delete and bleed it when the wife comes home Tuesday.