Break job from H _ _ _ _ ! (Page 1/2)
Signupacct SEP 14, 11:20 PM
I am writing because I am at my wits end. If I ever have another repair restore issue like this that takes as long as this and stumps as many as this then look for a listing of this car in bring a trailer or bring a crusher.

My son came home with a very weak pedal that lost pressure suddenly and his pumping the brake pedal in response produced some but not a lot of stopping power so he used mostly emergency brake to get home.

We assumed a bad master cylinder on a 40 year old car and with no knowledge of what the seller may or may not have done with brakes we decided to do a total brake job. They weren’t that great and couldn’t lock up brakes and stopping power and pedal not great to begin with and in addition to doing a complete brake job we decided to do a S10 upgrade rather than stock oem booster

Our goals were to fix whatever issue that caused the loss of brake pedal suddenly, address any deficiencies related to any previous work done by previous owners or their mechanics, improve stopping/braking performance and improve pedal feel.

Many owners on the forum share same complaint as I did leading up to this brake failure, poor braking performance, standing on the pedal and not able to lock up the brakes, close calls avoiding collisions with other vehicles stopping suddenly.

So the work began.
New rotors pads discs calipers and new master cylinder and new S10 booster. And also new SS brake hoses from fiero store. We also used Rodney Dickman booster kit and bought both adapters and even clicked on the link on his page to buy the S10 booster from Summit racing. Based on measurements in the support material one of the extension rods was chosen and the S10 booster and pedal brake rod was nearly identical in length as the oem.

After flushing out the system and lines etc we try to bleed
the brakes we get good results after bleeding the rear brakes good pedal and then go to the front right wheel and first bleeding we get fluid and air, close the bleeding valve and lose the pedal we had and nothing comes out of the line when the bleeder valve is re-opened.


We check and double check if all the lines are tight and no leaks etc. no luck second time bleeding. Change out the new master cylinder with another new one. Same symptoms. So the we do the whole “maybe it’s the proportioning valve” thing and we get a wet one pulled off another fiero being parted out for other reasons and same symptoms. So then it’s recommended that the proportioning valve needs to be locked down during bleeding so we get the screw in plug/pin from Amazon and it screws into where the brake light sensor goes and that pin locks the slider in the valve in the center so it cant interfere with bleeding front or rear brakes . Try again and same symptoms.

So the we do the "hey the proportioning valve is crap design anyway" and so lets change out the oem proportioning valve for a wilwood with the knob for the rear brake adjust 260-11179

The front rear bias as set from factory is implicated as a cause for the longer braking distance 50 to 0 and 70 to 0 etc.

In changing out the wilwood also replaced the front driver side hard brake line as it didnt seem to have a good flow of fluid when we were flushing our the lines.

Installed wilwood and still same symptoms

I am not a parts changer when it comes to trouble shooting, and other mechanics that I have talked to say there are times when parts changing is the best way and sometimes the only way. A lot of parts counter help and mechanics have said that the quality of the parts coming from China and elsewhere is not that great and defect rates are high. They are also say that the calipers and other parts can be defective and not leak but can also let air into the system. Hence, parts changing in a process of elimination is what others say they resort to.

The only things left that I can think of is to put the oem booster back in or replace the master cylinder.

Thoughts suggestions on completing a brake job that should have taken four weekends at the most not four months

Joe k

[This message has been edited by Signupacct (edited 09-14-2024).]

jelly2m8 SEP 15, 03:55 AM
Wooo Woooo Woooo

A too long read that took several rereads..... slow it down, break it up. You state 'you are not a parts changer', but your post says so.

First, do not swap to a S10 brake booster to fix a problem ( I am a HUGE proponent of swapping to a A S10 booster BUT ONLY AFTER the factory system is 100 % )


you are at a point forget the parts you that you threw at it Relay to us what is happening exactly, again, refrain from al the new parts.
BTW, Expert advice, trash the "braided brake lines' and get new OEM or equitant from Rock Auto and eliminate that future failure now
cartercarbaficionado SEP 15, 04:09 AM

quote
Originally posted by Signupacct:

I am writing because I am at my wits end. If I ever have another repair restore issue like this that takes as long as this and stumps as many as this then look for a listing of this car in bring a trailer or bring a crusher.

My son came home with a very weak pedal that lost pressure suddenly and his pumping the brake pedal in response produced some but not a lot of stopping power so he used mostly emergency brake to get home.

We assumed a bad master cylinder on a 40 year old car and with no knowledge of what the seller may or may not have done with brakes we decided to do a total brake job. They weren’t that great and couldn’t lock up brakes and stopping power and pedal not great to begin with and in addition to doing a complete brake job we decided to do a S10 upgrade rather than stock oem booster

Our goals were to fix whatever issue that caused the loss of brake pedal suddenly, address any deficiencies related to any previous work done by previous owners or their mechanics, improve stopping/braking performance and improve pedal feel.

Many owners on the forum share same complaint as I did leading up to this brake failure, poor braking performance, standing on the pedal and not able to lock up the brakes, close calls avoiding collisions with other vehicles stopping suddenly.

So the work began.
New rotors pads discs calipers and new master cylinder and new S10 booster. And also new SS brake hoses from fiero store. We also used Rodney Dickman booster kit and bought both adapters and even clicked on the link on his page to buy the S10 booster from Summit racing. Based on measurements in the support material one of the extension rods was chosen and the S10 booster and pedal brake rod was nearly identical in length as the oem.

After flushing out the system and lines etc we try to bleed
the brakes we get good results after bleeding the rear brakes good pedal and then go to the front right wheel and first bleeding we get fluid and air, close the bleeding valve and lose the pedal we had and nothing comes out of the line when the bleeder valve is re-opened.


We check and double check if all the lines are tight and no leaks etc. no luck second time bleeding. Change out the new master cylinder with another new one. Same symptoms. So the we do the whole “maybe it’s the proportioning valve” thing and we get a wet one pulled off another fiero being parted out for other reasons and same symptoms. So then it’s recommended that the proportioning valve needs to be locked down during bleeding so we get the screw in plug/pin from Amazon and it screws into where the brake light sensor goes and that pin locks the slider in the valve in the center so it cant interfere with bleeding front or rear brakes . Try again and same symptoms.

So the we do the "hey the proportioning valve is crap design anyway" and so lets change out the oem proportioning valve for a wilwood with the knob for the rear brake adjust 260-11179

The front rear bias as set from factory is implicated as a cause for the longer braking distance 50 to 0 and 70 to 0 etc.

In changing out the wilwood also replaced the front driver side hard brake line as it didnt seem to have a good flow of fluid when we were flushing our the lines.

Installed wilwood and still same symptoms

I am not a parts changer when it comes to trouble shooting, and other mechanics that I have talked to say there are times when parts changing is the best way and sometimes the only way. A lot of parts counter help and mechanics have said that the quality of the parts coming from China and elsewhere is not that great and defect rates are high. They are also say that the calipers and other parts can be defective and not leak but can also let air into the system. Hence, parts changing in a process of elimination is what others say they resort to.

The only things left that I can think of is to put the oem booster back in or replace the master cylinder.

Thoughts suggestions on completing a brake job that should have taken four weekends at the most not four months

Joe k



loss of pressure that can be made up with pumping is almost always an internal leak inside the master cylinder.
did you bench bleed this master or no? also check both sides of the brake lines by loosening the hardline going into the braided section
1985 Fiero GT SEP 15, 09:40 AM

quote
Originally posted by Signupacct:

Many owners on the forum share same complaint as I did leading up to this brake failure, poor braking performance, standing on the pedal and not able to lock up the brakes, close calls avoiding collisions with other vehicles stopping suddenly.





One thing to note, locked up brakes are not the best brakes, and while a factory new Fiero may have been able to lock up the brakes, remember that modern tires are much stickier, making the brakes feel more inadequate, even if stopping distances are the same or better than when brand new. Brake pad material are also essential in driver feel, done brake pads will make the brakes feel horrible, some will make the brakes lock up easily (I've heard good things about Fiero store carbomet, Wagner Thermoquiet, and I use Bosch quiet cast semi metallic, capable of locking up, with no dust or noise on brand new tires) that won't fix your actual problems, but it'll give you better expectations on what to expect for your brakes to be like.
82-T/A [At Work] SEP 15, 03:19 PM

quote
Originally posted by Signupacct:

Many owners on the forum share same complaint as I did leading up to this brake failure, poor braking performance, standing on the pedal and not able to lock up the brakes, close calls avoiding collisions with other vehicles stopping suddenly.




I find this interesting... I've owned about 9 Fieros of various models (never an 88) and I've never had the problem you experience. I don't know that locking up the brakes is something to be desired (personally), but I've never had problems with my Fiero being able to stop when things were correct. For the record, when I owned all these cars, I drove them really, really hard. Floored at every light, slammed on the brakes before every stop light, peeled out at every light, multiple run-ups to 120mph on highways... essentially what you'd expect an extremely immature and irresponsible 19-20 year old to be doing.

The only time I've ever experienced what you're talking about, is when my brake rotors were completely glazed over due to excess heat... as in, the brakes are literally smoking at a stop light (I see smoke coming up from front left and front right).

The Fiero's brakes are not complicated, like... at all. They're really quite simple, and they're quite good for being stock brakes. There were almost no cars at that time that had four wheel disc brakes back in ~1984. Just make sure you're doing everything properly... as in, properly bleeding the brakes, master cyl, etc., not installing garbage rotors or calipers, and making sure that you have vacuum at the brake booster.


Also... respectfully. I'm not sure that coming onto a forum and shitting all over the "main theme" of what the forum is about, is a good way to get support. I realize you're frustrated. But when you were younger trying to let your parents go to that concert or loan you cash for the weekend... did you tear into them and tell them how crappy they were before you asked them for money or to let you go to the concert? Obviously, we're not your parents... but normally a post like this should start off like, "Hey guys... I could really use your help. I'm banging my head against a wall..."

[This message has been edited by 82-T/A [At Work] (edited 09-15-2024).]

Mike in Sydney SEP 15, 07:56 PM

quote
Originally posted by 82-T/A [At Work]:


The Fiero's brakes are not complicated, like... at all. They're really quite simple, and they're quite good for being stock brakes. There were almost no cars at that time that had four wheel disc brakes back in ~1984. Just make sure you're doing everything properly... as in, properly bleeding the brakes, master cyl, etc., not installing garbage rotors or calipers, and making sure that you have vacuum at the brake booster.




Are you following the proper bleeding sequence?

There has been a lot of talk before on what the correct sequence is. You should start with the calliper furtherest away from the master cylinder. The manual say the sequence is: RR, LR, RF, LF. But it's been pointed out to me the correct sequence is LR, RR, RF, LF. This is because the routing of the brake lines makes the left rear calliper furtherest away from the master cylinder in the brakeline network.

I'm not sure if the RR, LR, RF, LF sequence or LR, RR, RF, LF sequence makes a hill of beans but I've been following that practice for a while with good results. Just make sure everything is working good before you bleed the system.

Cartercardafficianado mentioned bench bleeding the master cylinder. This is always a "must do" when replacing it. If you've not done that, try starting there.

Check your vacuum lines on the brake booster and if you didn't do it, replace the brake booster filter going into the booster itself. You may not need it but hey, new booster, new filter. Autozone has these for around 12-15 bux.

Next to electrical gremlins, vacuum leaks, failing ICMs, and faulty fuel pumps, I find brakes are the worst to troubleshoot. Just hang in there. You'll solve it and when you do, let us know what the solution is so we can add it to the PFF knowledge base.

[This message has been edited by Mike in Sydney (edited 09-15-2024).]

Patrick SEP 15, 08:41 PM

quote
Originally posted by 82-T/A [At Work]:

Also... respectfully. I'm not sure that coming onto a forum and shitting all over the "main theme" of what the forum is about, is a good way to get support. I realize you're frustrated. But when you were younger trying to let your parents go to that concert or loan you cash for the weekend... did you tear into them and tell them how crappy they were before you asked them for money or to let you go to the concert? Obviously, we're not your parents... but normally a post like this should start off like, "Hey guys... I could really use your help. I'm banging my head against a wall..."



What am I missing here? I've read the opening post over a couple times and I don't see what it is that you're suggesting.

82-T/A [At Work] SEP 16, 09:18 AM

quote
Originally posted by Patrick:

What am I missing here? I've read the opening post over a couple times and I don't see what it is that you're suggesting.




I may have just misread... but it looks like the thread had been edited. I responded much later than when I first read it. But again, I could have just misread it. I've been traveling a lot and short-tempered, haha. I thought I read something about the car inherently having poor design, and all that. But again, maybe I just misread.
Signupacct SEP 17, 03:00 PM
Ok here is an update and answers to specific questions asked and relevant comments:

First, when my son came home using the emergency brake because of a failing brake pedal pressure, the initial thought was Hey we were already thinking about addressing the performance of the brakes and the unknown history of the car and decided that so much of the system is going to be replaced why spend a lot of time figuring out why it had the symptoms it had. I read in the forum that the symptoms he experienced were more than likely the master cylinder and since that, the calipers, discs and pads and lines were planing to be replaced it didnt seem like it would have been relevant.

I have worked on cars since I was 16 and I have had mostly and always preferred GM cars, two GTO's, a Beretta, two Chevy pickups and brake jobs were always straight forward processes with success easily attained. This fiero is a gift from my son and I was initially excited about having it. It was lowered in the front (springs and bump stops cut) and so it spent the first four months in the garage related to reversing this so the car could be driven with OEM clearance. Never got the front springs right (they are too stiff) and that is for another discussion, then the a/c goes out and again several months out of commission gathering the parts etc. then this last winter it got near freezing and the shifter could not change the gears properly and it somehow locked up in two gears simultaneous. Archie, after missing most of the last winter's season to this event, walked me through getting it up on jacks (even in an incline of the driveway) and were able to rock the wheels back and forth till it got unstuck. Still have the shift cables ready to go from Rodney etc. And then as we got that issue under control then the brakes fail.

And in my wildest thoughts did I ever imagine changing the number of parts that we have and still not have a pedal. So yes I want to fall in love with a car that can love me back and so look forward to getting this brake thing behind us and perhaps enjoy the car driving it as opposed to turning wrenches on it.

Before ever writing in the forum about this, I read the relevant posts that I could find. Made a donation to the forum etc. I read the one regarding changing the OEM proportioning valve for the Wildwood. Another regarding the SS versus OEM hoses. Other posts I read considered the possibility of clogged hard lines. Consulted with Fiero store, Archie, and Wilwood. I talked to a number of experienced counter help, and certified mechanics that I respect and all have complained that the quality of the parts is not what it used to be and going through one or two and sometimes three parts before getting a good one is not unheard of. So with the quality of the new parts a new variable, some of those I have tapped for advice say parts changing is one way of contending with it.

So it is then that I had become frustrated.

I really appreciate MOST of the comments (one gets an eye roll) and many made helpful points and also offered good tips.

I agree that the move to the S10 booster should have occurred after the dust settled. And should have taken that approach.

Yes, I bench bled the Master Cylinder according to the instructions. Yes I am following the farthest from the master cylinder order, the one that considers that becuase of the single line to the splitter that the starting point is the LR.

Yes I replaced the front driver side hard line because the flow when flushing was not that good visually.

I have put a new OEM booster in place of the S10 and still same symptoms.

Here are the symptoms: we start bleeding at the LR and get really good flow of solid fluid when opening the bleeder valve and a good pedal after bleeding both rear calipers. Then we go to the front passenger side and we open the valve and get a good flow of both air and fluid the first time we bleed there. After closing the valve and try pumping the brake pedal to get ready to open the bleeder valve, the pedal we had as a result of bleeding the rear calipers is lost and when we open the valve nothing comes out.

That is where we are.

Only thing left is to replace the master cylinder ( which will be the second one) and bench bleed before installing

and go back through and double check all the fittings and make sure there are no leaks

and see where we are.


Joe k.

[This message has been edited by Signupacct (edited 09-17-2024).]

cartercarbaficionado SEP 17, 11:18 PM
ah. that's a symptom of air still. please bleed at the output of the proportioning valve by loosening the flare nut while pressing the brake. then try bleeding again and let Me know what happens. I had this happen on my s10 blazer and a 2001 gtp and one of those needed the hard lines replaced because of a small pinhole causing a pressure loss
edit: really really dumb idea came into my head. is the proportioning valve actually installed the right way around since it can block off fronts or rears when detecting a fluid pressure difference but usually locks the rears first

[This message has been edited by cartercarbaficionado (edited 09-17-2024).]