Brake softness?

[DirtRoadTrip]

Quick question for you guys. I just had my stock brake fluid swapped out for Castrol SRF. I was without the car for a couple of days, so I didn't get to go back to back. I swear now the brakes feel a bit "softer" and I expected the opposite. With the car running, I can, with hard pressure, get the pedal to go all the way down. I don't remember it doing that before. From a low speed (40mph), I was still able to threshold brake/get into ABS without the pedal going to the floor.

Thoughts? Can someone remind me what the car does stock? I'll be running at Watkins Glen next weekend so I want to be confident there's not an issue.

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[GTthree50]

Im definitely no expert here but that sounds like air in the lines.

 

[jgedde]

Quick question for you guys. I just had my stock brake fluid swapped out for Castrol SRF. I was without the car for a couple of days, so I didn't get to go back to back. I swear now the brakes feel a bit "softer" and I expected the opposite. With the car running, I can, with hard pressure, get the pedal to go all the way down. I don't remember it doing that before. From a low speed (40mph), I was still able to threshold brake/get into ABS without the pedal going to the floor.

Thoughts? Can someone remind me what the car does stock? I'll be running at Watkins Glen next weekend so I want to be confident there's not an issue.

Sounds like air in the lines. Different brake fluids at normal operating temperatures will not result in a change in pedal feel. When the fluid boils, it's another matter. That's where the premium fluids come into their own - higher boiling point.

John

 

[Tank]

Im definitely no expert here but that sounds like air in the lines.

+1. Did you bleed pass rear , drivers rear, pass front, drivers front? Also with the SRF, did it take the full bottle then some out of a second?

 

[DirtRoadTrip]

+1. Did you bleed pass rear , drivers rear, pass front, drivers front? Also with the SRF, did it take the full bottle then some out of a second?

I had a shop do it. I provided 2 bottles of SRF. They used both bottles.

 

[cjgt350]

Did they bleed both the outside then inside bleed screw for each corner? Many shops are not accustomed to two bleed screws per caliper.

 

[cking]

Another classic case of this car is too complicated to get good service.

 

[DirtRoadTrip]

I just did 3 things... First took the car for another spin, confirmed that the car is still exceeding the traction limit of the tires under hard braking, and my foot is not hitting the floor in those situations, so that's good. Second, for reference, I tested the pedal firmness in my 4Runner, and it is waaaay softer, yet the truck will also get into the ABS.

Third, I talked to the shop. They bled the inner and out calipers in the appropriate order. However, they want to see the car again and re-bleed, to 100% confirm there is no air in the lines given it is being tracked next week. They said there is a little bit of fluid left over from the second bottle. I'm bringing it back in early Tuesday AM for that work. So we'll see if I am making things up, or if there is in fact a little air in there.

 

[kart125]

Agree sounds like air in system. Try to do a brake/quick release/brake again. If pedal feels firm after quick release/brake it's definitely air in the system. On the first brake application the air gets compressed along with the non-compressible fluid, giving the mushy feel. quickly releasing and reapplying the brakes will add more fluid in the compressed system, giving a firmer pedal feel. Spongy feel resumes on next brake apply since air expands again. If pedal does not go to the floor it's an easy fix (rebleed the brakes properly). If pedal goes to floor slowly then it's a different story (MC fail/ABS module fail...). The shop should fix it easily... pretty sure bubbles are going to come out. It could be only one caliper that's not bled properly. Do they use a pressure/power bleeder?

 

[GT350Brakes.com]

That's one downside with Castrol, since it's fully synthetic, all of the non synthetic fluid has to be flushed out properly.

I personally siphon all of the fluid out of the reservoir before adding new fluid.

I'm sure with getting everything re-bled you'll be ok.

 

[Offboost]

Another comon issue with synthetic fluid is if the bottle was shook or just handled somewhat careless the fluid will get mixed with air. It will be someehat foamy or airated and even when bled the air is suspended in the fluid. The good news is when they rebleed it you probably wont have any more issues. Just make sure the poor the fluid in slowly and dont shake the can too much.

 

[mattlqx]

Another classic case of this car is too complicated to get good service.

There is nothing out-of-the-ordinary about how the brakes on the car operate or are serviced.

 

[snaproll]

That's one downside with Castrol, since it's fully synthetic, all of the non synthetic fluid has to be flushed out properly.

I personally siphon all of the fluid out of the reservoir before adding new fluid.

I'm sure with getting everything re-bled you'll be ok.

I believe SRF is compatible with most all fluids.

 

[JN66]

You fellas not happy with the OEM break fluid? I've ran the car pretty hard on a few different tracks and found its held up incredibly well.

 

[FordTechOne]

Ford recommends using a pressure bleeder to ensure that all air is removed from the brake system after service. Sometimes traditional vacuum/manual bleed procedures cannot extract all air, especially if the system ingested air during the brake fluid change.

If the brake fluid reservoir went dry during the brake fluid change, you may have also introduced air into the HCU. When that occurs, you need to perform a pressure bleed, then perform the HCU bleed procedure with the IDS, then perform another pressure bleed.

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