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Topic: 5 lug converstion complete (Read 8284 times) previous topic - next topic

5 lug converstion complete

we converted my sons 88sport from 4 to 5 lug

used the PBR dual piston calipers up front and varga out rear,, all is well with that swap.


We began bleeding our brakes and everything was perfect with the car off and bleeding.

when we started the car,, the pedal goes nearly to the floor when we need to stop.

we are on our 4th qt of brake fluid now,, and we are stumped.
We decided to check for flow from the master and I discovered the front side fitting had no fluid coming out when braking so we swapped out the master cyl.

we bench bled the master then installed, then we finished bleeding the individual wheels with the car off.
when the car is started, the pedal goes to the floor again,, when brakes are needed.


the booster has always had a hiss noise when the brake is applied,, but something has me thinking the booster is bad,,, I have no idea at this point what to do


HELP!!!!!!!!  son has to be back to work on Monday.

5 lug converstion complete

Reply #1 –
Are you using the stock master cylinder with the upgraded brakes?

5 lug converstion complete

Reply #2 –
The Booster sounds like it might be bad. Try disconnecting the vacuum and see if it still does it. If it does the Booster is bad.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

5 lug converstion complete

Reply #3 –
Quote from: bodyman;455718
Are you using the stock master cylinder with the upgraded brakes?

yes

5 lug converstion complete

Reply #4 –
Quote from: Haystack;455722
The Booster sounds like it might be bad. Try disconnecting the vacuum and see if it still does it. If it does the Booster is bad.

that would put me in manual brakes mode,,, would have to plug off the vac line

5 lug converstion complete

Reply #5 –
so...

with this upgrade we go from two pistons  & two wheel cylinders to .................

6 pistons to make brakes...........

we disconnected the rear brakes and they no longer are in the picture for troubleshooting purposes....
we are now sending fluid out to the two front wheels and the same symptom,, while the car is running the pedal goes deep to the floor.. its not easy to get there but does take little effort to make it eventually bleed down to the floor.

the booster seems bad.... man I wish we had not have done this project this week.
we gave ourselves a full week to do this swap and if its not one thing its another.

5 lug converstion complete

Reply #6 –
mason is on the way back with a 94 mustang master cyl,, I discovered the ford bronco reservoir is the same style so I can steal that off my  bronco to fit on the master,, our stock masters / reservoirs are "stepped" so to speak.

I just told him the bad news,, not sure how he is going to get home in time for work now.

5 lug converstion complete

Reply #7 –
Yeah, you've got to have the matching master cylinder.  It has to do with cylinder volume at each end of the circuit shaging up the hydraulic ratios.  There's also a metering block to deal with, some masters would instead have the metering valve built into the outlet for the rear circuit.  15 years ago when I'd just gotten out of college, I could have explained that better, but I think I'm still pretty close.

5 lug converstion complete

Reply #8 –
Foe

I just discovered something that **correct me if im wrong***,,,,,, the 1990 ford bronco master has everything we are looking for.

has a metering valve on the rear side outlet,,, has a outlet at the front side,,,,, has a blank on the bottom center.

would mount the same and would be more of an upgrade.

just trying to think about options.....

does is sound like the booster went to  to you to?

haven't been on the board in a few months,,, been working away for 8months straight

take a look at it on rock auto,, they have pretty good / accurate pics

5 lug converstion complete

Reply #9 –
I think if the booster went bad you would have lack of or no assist, not more or less overall pedal travel.

As far as master cylinders I think it is more important to look at bore size and pedal ratios. I think you are going in the right direction with the Mustang master being it was designed for twin piston fronts and rear discs. You may want to consider changing the pedal ratio to get the correct pedal travel and feel.  Here is the info Jack Hidley provided me for mounting the mustang hydro boost and master for my swap.

Quote
I think you are going to have one problem with the hydroboost installation. All of the 1987-88 T-Birds have a 3.5:1 pedal ratio. That is the pedal pad moves 3.5 units for each unit that it pushes the m/c pushrod. I do not have the data for your 1985 2.3l turbo, but I assume it is the same. You can check you pedal ratio be measuring the physical brake pedal dimensions and dividing one by the other.

 The Mustang that you pulled the hydroboost unit from has a pedal ratio of 4.75:1.

 Since you appear to have connected the hydroboost unit pushrod to the 3.5:1 pedal pin, the required pedal effort and travel is going to be quite a bit different than what Ford designed. The brake pedal effort is going to be 36% (4.75/3.5) higher. The travel at the pedal pad is going to be reduced by the same amount.

 To correctly fix this, the pin on the brake pedal should be moved upwards slightly less than 1" (0.97") and the hydroboost unit should be raised on the firewall to correctly align the pushrod so it is straight
.

5 lug converstion complete

Reply #10 –
Quote
the booster has always had a hiss noise when the brake is applied,, but something has me thinking the booster is bad


Does the car have the automatic parking brake option? Check the B/R port on the vacuum tee under the hood...if it's not capped off and has a line on it, follow that into the firewall and under the dash, driver's side, by where the steering column goes through the firewall. You'll find a white-colored semicircle; that's the auto parking brake release. It may be bad, or the vacuum line may be bad, and that could be what you're hearing.

Otherwise it seems you have a bad booster, and new parts likely brought out the worst in it.[/COLOR]

5 lug converstion complete

Reply #11 –
his car does not have auto brake

my 20th does,, it works fine on my 20th

5 lug converstion complete

Reply #12 –
Quote from: bodyman;455731
I think if the booster went bad you would have lack of or no assist, not more or less overall pedal travel.

As far as master cylinders I think it is more important to look at bore size and pedal ratios. I think you are going in the right direction with the Mustang master being it was designed for twin piston fronts and rear discs. You may want to consider changing the pedal ratio to get the correct pedal travel and feel.  Here is the info Jack Hidley provided me for mounting the mustang hydro boost and master for my swap.

.




great post!



Update,
we are going to swap in my spare booster tomorrow
we are going to install the new master tomorrow with pivot pin relocation ,, since this one has two ports only we have to do some line work with a Tee but that's pretty simple and then keep the combo valve for now.... although I feel like it needs gutted in trade for the adjustable option later down the road.

we are going to use my ford bronco reservoir


the more I think about that stupid combo valve and how many times it has proven to not function due to whatever reasons,, I feel like gutting it.



at this point I am assuming the booster is bad, still not really completely sure though,, like how do you troubleshoot it.

when we pump the pedal with the vac check valve out, it blows out air ad sucks in air.  *car off that is

same holds true with my 20th when we compare that car to the bird

5 lug converstion complete

Reply #13 –
Also guys,, from what I remember here, or on the web somewhere,,
when you remove the master cyl,, there you reveal the booster pin.

now If you look closely at the pin,, its actually a round ball head "bolt" threaded into a tube.  I recall someone here stating the benefits of adjusting the booster pin out more for some reasons about better breaking and such.