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.
Are you using the stock master cylinder with the upgraded brakes?
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
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.
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.
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.
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
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.
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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]
his car does not have auto brake
my 20th does,, it works fine on my 20th
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
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.
I think it's best to use the Mustang master that matches the new brake setup. If the reservoir is a problem, get one. They're not expensive.
There is a valve that tells the Booster how much assist to give. When that valve or seal goes bad, the pedal sinks to the floor. You are getting too much assist, not not at all.
Like I said, pull the vacuum line off and all will be well. Not saying you should, but it wouldn't bother me a bit to drive with the Booster bypassed for a week or two as long as I knew it was there. You can still lock up the brakes, it won't be impossible to stop or drive in traffic, everything will be exactly the same as it is now just with more pedal power required. It's there is old ladies don't have a hard time holding the brake pedal down during rush hour.
UPDATE I forgot,,
when we start the bird up and do our thing pumping brakes and such,, then shut off the car,,,
when we undo the check valve on the booster,,, there is a bunch of air that rushes into the booster opening where the check valve was.
this tells me the diaphragm is not blown!!!
or am I missing something.....?
we don't want to waste time doing a booster if its not bad and all that is wrong is the combo of parts...
so ,,, if the booster holds vac pressure then it should be ok,,???
It is possible that the booster is holding vacuum until the pedal is applied and then leaking around a seal as they are applied. The leak is small enough that they are providing the boost needed and not causing any other issues. The only thing the booster is going to effect is the ease of application of the brakes. It is not the reason your pedal is going to the floor but it is helping you get it there.
To correctly change the pedal ratio you are most likely going to have to relocate the booster and master on the fire wall to keep the pedal rod correctly aligned. If you are in doubt about the booster it's not a bad time to change it out anyway.
There are some good threads on here about upgrading the brakes, and the booster. Most upgrade to the 93 mustang cobra booster or mod the firewall and install the 94 up booster.
did some self pace training today on web vids showing how to determine if the brake booster is bad or not.
ours passed
so we kept it.
we installed the 2004 pony master cyl and we had only the front brakes tied in.
all is well in the world of braking ...........except 1 part,, the old bone yard calipers are sticking.
so .. tomorrow we will attempt to take out the pistons, do some corrosion control and put them back together.
we have another option which is to buy reman or new if they are on the shelf tomorrow or Monday morning.,, otherwise, we are going to use our time wisely to see if we can wake up these front dual piston calipers which are basically locking up the front wheels.
so,, even though it sounds bad,, progress was made.
we just now finished up,,,
This 5lug swap project is done.
we spent more time than I thought would even come close to reasonable but its all good.
The biggest and best adjustment to fine tune things is the booster rod,, we got rid of all the take up and man are these breaks the best!!
we omitted the combination valve completely and made an adjustable unit which now lives where the old combo valve was.
We played around with adjustments to the rear varga's and finally settled on wide open,, that may change later if mason decides to but......... I have never had these cars stop so level ever.
thanks everyone!
I need to do a brake swap. Mine suck. Tiny little stock brakes.
Update,
so we now understand more about assisting brakes and its becoming more clear to me now why a cobra booster would be the next logical and final step.
this is on the table for the next time mason is back home.
I will post pics soon of all this.
Be careful as too much rear brake bias will tend to lockup on a wet surface...
I will back pedal some pictures here now that mason is on the way back to Charlottesville Va
here are a few pics of starting up the project
our application was a 88tbird sport with a 2.73 trac loc 7.5'' rear ,, going to 4wheel disc brakes with PBR calipers up front both having dual pistons and using Varga in the rear which have single pistons.
visually you will see the s-shaped spring in the middle of the gear set along with small tabs of clutch plates on the right.... and yes both wheels roll in the same direction when one is turned in that direction.
This is what you don't want to learn after nearly a year of planning out parts.
you must confirm your parts list for the rear by deciding if you are "5lug keeping drum" or going "5lug going disc"
we did not know any better and thought incorrectly.
Here you see our first problem was 5lug axles that are exactly the same length as original 4lug axles. this would be fine if we were keeping rear drum. these 5lug axles were given to us free.,, no good though for our application.
to fix the problem, you buy summit axles by two choices,, one set is 30.63'' 28spline(summit brand) long and the other is 30.75'' 28spline (higher end brand) which actually is the perfect length for the job.
We were forced to use the 30.63'' long 28spline axles due to what was in stock and next day air shipping of 75$.
--the bonus is that summit also provides you at no extra cost the correct rear bearings and seals on their branded axle.
Fully inserted then c-clip installed then pulling back on the axle to take up slack, the rotors would rub the rear caliper.
-the fix, 1/8'' shims over top your axle studs then install the rotor and its all perfect.
**do not ever purchase the rear axle bearing / wheel seal "combo kit" ,, it sucks ass berries badly. only install the skinny 1/2'' wide axle bearing and a separate seal.
the next two pictures show how our incorrect axles could not insert fully into the their home because the "additional" shoulder flair on the axle prevented us from fully inserting into the axle tube because we kept hitting the axle outside seal.
No matter what your told, I am very certain the need for inner tie rod ends is mandatory,, you have to buy them.
The replacement spindles orient the geometry of the outer tie rod end that if you "kept" your old inner tie rod ends, your replacement outer tie rod ends in my opinion would not catch enough threads.
With that being said, its your call.
Strut fitment has three problems to work through.
-the mounting holes on your replacement spindle are 1/8'' closer center to center than your old spindles.
to fix you install the lower strut bolt, then file out the upper strut opening along the top side to finally allow the bolt to go in.
-Your replacement spindle strut mount hunk of steel is more skinny than your original leaving you to think about two options.
to fix don't just cinch down the bolts to crush the strut because you will never get the bolts out easy later. add 1/8'' flat washers to the strut mounting bolts to take up the difference.
-once you set your strut you notice that the lower ball joint nut is going to bump into the lower part of the strut.
to fix you add the flat washers mentioned above to the correct side of the strut and this will fix the issue.
also to fix, if you happen to collect old hardware like me, you may have the "smaller" type ball joint nuts. I have seen two ball joint nuts, there is one that is fat and one that is skinny and one of these is also a tad shorter... your choice on which you use.
Here is how we solved the rear caliper brake hose attachment.
simply reuse the existing hole that is currently clamping down your existing brake line.
this may not suit you but we were satisfied with this layout for both sides.
due to the design of the hose assembly, mounting as shown mostly if not 100% puts the metal plate in a "locked down" bind.
simply cut your existing line back and provide new fittings as required and do bubble flairs.
to rework brake line connections all your lines are considered 3/16'' fittings. I purchased several boxes of fittings in advance that fit the old original stuff that's on the car plus fittings that are compatible for early / late SN95 donor parts.
either way you will need new fittings for your brake hose transitions and your existing lines.
********NOT SHOWN HERE>> up front your existing front caliper metal bracket that transitions you from a rubber to metal hose,, take out that bracket and then using a stepper drill bit, you must drill out the hole to accommodate the larger and "hexagon" shaped front caliper hose fitting. once done you can now insert your new brake line and add the old clip to hold it in place. the down side is from now on you have to hold the brake line with a wrench while loosening the hard line with a line wrench but we do not see this as too big of an issue.
the next two pictures show how we overcame a few problems.
you can use an early SN95 master cyl which has two fittings. newer SN95 masters have everything sideways or 90 degrees out of phase.
you can use a 93cobra master cyl
**I don't personally see any net gain in using a 93cobra master
each above have the same fluid reservoir
YOU MUST buy a new master cylinder if going disc all the way around. if your keeping drum in the rear then you "might" be ok with your stock smaller cylinder bore master.
Delete your existing combination valve
the front fitting on your master cyl ********IS larger but **is 3/16'' line.
the front fitting transitions through your combo valve and turns into 1/4'' line!!!! know this and be prepared when you make your new rear adjustment valve.
your adjustment valve should be ready to accept 1/4'' line coming in from the rear and 3/16'' line out and up to the front fitting of the master.
**an option I "would have" done is change the 3/16'' short section of line to 1/4'' but I had no 1/4'' fittings on hand to screw into the master.
We started doing our test runs for brakes with the rear fitting wide open,, over time my son will reduce the fluid delivery to the rear when he notices the rear is locking up in wet road conditions or snow ect.
The rear fitting on our chosen early sn95 master cyl has a Tee installed such that we are now a home run dedicated line to each front wheel with the common feed line from the master cyl.
in some areas we used the nickel copper brake line available at the parts stores... flairs so nice!!
this does not in my opinion look pretty ,, we were screwed for time.
once your done, you bleed your brakes with your on hand nearly 3 qts of brake fluid because if your like us you had to take things out a couple times and discover the hard way your master is wrong and all that stuff, which is the reason I am typing all this up,,, so you hopefully dig up and read this thread.
Now its time to test drive and you discover your pedal ishiznitting brake just about the same place as before.... feeling like "why did I do this when everything feels the same".
loosen up the master cyl and pull it away from the booster.
study the little actuator rod and you will see its actually a bolt with a rounded / hex head.
with vise grips, steady the outside "rod" and with a wrench rotate the screw counter clock wise one turn at a time.
bolt the master back down.
put the car on a level surface.
start car and put it in gear... if the car rolls forward and back on its own with no brake applied, repeat the adjustment.
once the car is *****barely*** binding up with no brake applied, then pull the master back off and screw the adjustment **BACK IN** a half turn.
retest then drive the car.
your results should be an almost instantaneous feeling of braking power when your foot barely pushes on the brake.
Now that your hitting good brakes ,, your thinking that the effort to stop the car seems a tad ,, and I mean a "TAD" more strenuous to do.
that's because your foot is now a bit higher hitting the brake and your not use to it.
also,,, A cobra booster which has a dual diaphragm system would give you more vacuum assist than your stock unit. That being said ,, we are going to do a cobra booster next up when mason comes back home.
completed pics
absolutely none of this would have been possible without the help from this board.
Special thanks to Turbocoupe5.0,,, Ericcoolcats, & most special thanks to Aerocoupe!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Next up is a complete parts list applicable to ..........
"going 5lug disc all the way around" "using PBR dual piston up front and Vargo out back" for a 7.5 rear trac loc 2.73 rear.
Quick note, the 93 Cobra MC is a 1" bore unit where the 94-95 GT and 94-98 V6 MC's are a 1-1/16" bore unit. The preferred MC is one with a 1" bore like the 93-95 Cobra or the 85 Lincoln TC when going to the SN95 V6, GT or Cobra brakes.
With that being said I have 95 Mustang GT MC's on both of my cars with Cobra brakes and they stop just fine. It would be better with the 1" bore on the track but I doubt I would notice it on the street so its not gonna happen as I rarely get on a track.
When I did my 5 lug to my sport, I used axles from a '97 mustang. I remember it having the ABS rings, but a few taps with a hammer and those slide off. The axles of an SN95 (you'll want '94 to '98 only, '99-04 are too wide) are all the same, no difference between V6 and V8 (7.5 and 8.8), except for the ABS exciters.
I went drum brakes, so I used the Sport's backing plates, drums from an '89 Crown Victoria, and stock Tbird Sport brake shoes and hardware. I put some high quality brass washers over the lug studs under the drum, as the drum on side sat slightly too close to the backing plates and rubbed it. Otherwise, no issues.
For the front, if you need new ball joints, just use SN95 when you swap the spindles, that way you don't have to worry about adding washers to compensate for the longer Fox b/j, and the thinner SN95 spindle..
I never messed with the MC as I kept rear drums on my setups....I pretty much have the same setup on my notch, except the rears are the 9" drums rather than the 10".
There's not a way to get 10" drums on it with the existing axle length, and in any case, the car is for sale.
update
thus far, as a follow up, our elimination of the proportioning brake valve has had no ill effects on brake performance.
I think this is an inexpensive solution.