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Gearhead_Garage

Gearhead_Garage

Jedi Hopeful
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This forum has been very helpful to me while I sorted out the brakes on my BJ8 Phase I without a booster (basically BJ7 brakes). I thought I would share my experience for others.

Being an early BJ8, the car probably came with a brake booster but it did not have one when I bought the car. Even 20 years ago, the booster was NLA and I decided I could do without it since most Healeys were shipped that way.

The car was built with all new components including a BJ7 5/8" master cylinder. Despite all manner of bleeding, I always experienced excessive brake travel and inadequate deceleration. Perhaps I had a bad master cylinder.

Based on a forum search, to get a firm pedal, I swapped the master cylinder for the Lucas 7/8" unit from Moss, part number 581-100. It appears to be a higher quality component than the cheaper 5/8" and 7/8" units available from Moss but the line locations need some tweaking for connection. The larger diameter bore moves more fluid for the same pedal movement so the pads get snugged up with less movement. This should result in a firmer pedal at the expense of more effort required due to less hydraulic advantage.

After bench bleeding and installation, I finally got a rock hard pedal with very little travel. My enthusiasm was curbed when I drove it and it took Incredible Hulk levels of pressure to stop the car!

Back to the forum for some advice on more aggressive pads. I ordered up a set of Porterfield R4-S pads, installed and bedded them in. Wow, what a difference.

Finally, a stiff pedal that allows good modulation and I can lock up the brakes if I press hard enough. Hopefully the dust won't be too bad.
 
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Glenn,
Thank you very much for this valuable information! I'm using ceramic pads on my 4-wheel disc setup with a 3/4" MC with easy pedal pressure. It's nice to know this can be done without adding the complexity of a servo.
 
I experienced the same long pedal throw before braking after installing a Moss-sourced 5/8" piston brake master cylinder, the standard for my '60 BN7. Bleeding didn't solve this. My thought, as expressed by Glenn, was that a larger piston would move more fluid and would reduce pedal movement. I installed a Moss-sourced TRW 7/8" master cylinder (part no. 581-100), which I understand is intended for servo-equipped later model Healeys. Since I had on hand a Victoria British-sourced servo kit, I installed that at the same time with the 7/8" master cylinder. This unfortunately masked the result I might have realized had I installed the 7/8" without the servo. I also rebuilt my front calipers that chose this period to start leaking. What I got from this conversion was a very short pedal throw before braking, but a rather heavy brake pedal. The braking is far superior to what I had previously experienced, with the sense that the front of the car pulls down quite briskly with brake application. I'm sure I could introduce a pretty pronounced skid if I use too much pressure. One difference between the TRW (and likey its Lucas equivalent) and the standard 5/8" MC my car had is that the push rod is adjustable. I adjusted mine so that the brake pedal was flush with the clutch pedal. I don't know who made my brake pads, but I will consider trying the Porterfield pads Glenn is using if they fit my calipers. I've related here previously that I have a left rear brake that seems to give an audible skid sound (it is closer to the driver's ear than the right rear) during braking. I examined that wheel's brake and didn't see anything suspect and even backed it off a couple of clicks with no change evident. It was suggested that I install steel-braided brake lines, and I did that without noticeable change, and also that my somewhat old tires might be the blame. Since all four tires appear to be identical, I don't think just one of them would tend to skid early. Something's at work here.
 
I'm gonna hijack your thread just a tad. The reason for different diameter MCs for servo'd and non-servo'd cars is force. Simplified explanation: if you have a MC with a piston of one inch of surface area and you apply 100lb. of force with your leg you are applying 100psi to the brake system. If you have a MC with a piston with 2 inches of surface area and apply the same 100lb. of force you are applying only 50psi to the system. That is why servo'd MCs are a larger bore; you need less pressure from your leg to activate the 'switching'--it 'switches' vacuum and ambient air--cylinder in the servo; the force of ambient air pressure against a vacuum is applying the rest. That's also why servo'd systems with a non-functioning servo are more difficult to slow/stop (my dad's '65 Mustang developed hard pedal/stopping, and he found out it was a cracked fitting from the vacuum line to the servo diaphragm; new fitting and problem solved).

Long pedal throw is usually caused by one or both of two things: drum brakes not adjusted properly and/or air in the system. I've completely rebuilt my BJ8's brake system over the years, and it generally performs properly. However, if I have to lock them up--last time was to keep from accidentally running a stoplight--one of the two rears will lock up first even though they are properly adjusted. I don't now if they're that finicky, but I adjust them one 'notch' on the adjuster from lockup, and one always feels a bit 'looser' than the other, but there's no way to adjust them any finer (another advantage of disk brakes). Our BN2 has drums all around, and it pulls to one side slightly if I stomp on them.
 
I went the other way and got great results. Remove booster downsize M/C to a manual brake size and add braided lines. Now I have a firm pedal , good modulation and a lot of dust.
 
bdcvg said:
I went the other way and got great results. Remove booster downsize M/C to a manual brake size and add braided lines. Now I have a firm pedal , good modulation and a lot of dust.
Click to expand...
This is the same thing I did; BN6 4-whl drums converted to MKI front discs/rear drums (non servo).

I was disappointed with pedal travel and firmness (the 4-whl drums were 1" pedal travel to rock/firm) thinking it was still air trapped in the calipers__and I know dry calipers take some effort to be fully bled.

Well not all that long ago, I replaced the rubber hoses due to the rear one swelling__really not that old either__with Teflon/braided stainless steel, and that made a tremendous difference! Maybe not quite to the firmness level I could keep the drums adjusted to, but I no longer feel compelled to automatically give it two (2) pumps per application.
 
My original post had an error (now corrected), an omission, and needs an update.

The part I installed was the Lucas 7/8" master, rather than 3/4" as I reported. Perhaps a 3/4" would have been a better choice. I'm not sure if you can mate an early 3/4" master to a later car.

I also installed all new stainless lines before changing the master cylinder. Rear brakes were checked and adjusted as tight as possible with just a smidge of drag. This helped a bit but did not deliver the firm pedal I was seeking.

Since living with the Porterfields for a week now I have made this observation. They stop great, WHEN HOT. These are a street performance compound but have some of Porterfield's racing DNA in them. The first couple of stops in the morning will require a high pedal effort until you warm up the pads. I have taken to dragging the brakes as I set out on a trip to get them warmed up before I need them.
 
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Glenn-
Thanks so much for that update. I have a firm brake pedal, but not particularly responsive brakes, so I have been closely following this thread. This is after installing new "Classic Gold Premium Ceramic Brake Pads" from Moss along with new calipers and rotors. After reading your first post, it occurred to me that perhaps I made an error on my pad purchase. What pads were you using before your Porterfields? Do you feel unsafe right now with the requirement of heating up the pads? My fear is freeway driving where you could go a long time between braking events. I want to be sure my car brakes effectively without excessive pedal pressure, so I am still not sure what pads I should be using.
 
I am a bit concerned about the cold start of the Porterfields also. I have strong legs so I can stop the car effectively but it might get old after a while. This weekend a friend recommended EBC greens or yellows. He says they don't need to get hot to work but the yellows tend to eat rotors.

I am not sure what pads were on the car when I got it. My restorer installed them. They look to be some type of semi-metallic, probably from Moss.
 
shortsguy1 said:
Glenn-
Thanks so much for that update. I have a firm brake pedal, but not particularly responsive brakes, so I have been closely following this thread. This is after installing new "Classic Gold Premium Ceramic Brake Pads" from Moss along with new calipers and rotors. After reading your first post, it occurred to me that perhaps I made an error on my pad purchase. What pads were you using before your Porterfields? Do you feel unsafe right now with the requirement of heating up the pads? My fear is freeway driving where you could go a long time between braking events. I want to be sure my car brakes effectively without excessive pedal pressure, so I am still not sure what pads I should be using.
Click to expand...

Did you follow the recommended break-in procedure with the ceramic pads? If you didn't and didn't get such a thing from Moss, there are plenty of instructions online. I have broken-in Centric ceramic pads and they perform great.
 
Thanks Glenn for that info. I clearly have a bit more homework to do.

Steve- That is a very good question. I can say I did my best to follow their directions, but they are unclear and difficult to follow (see below) . They say that you cannot come to a stop during the break-in process, but that you should cool the brakes with the car at rest. I found the inconsistency confusing. I also had trouble finding a road where you can do 8-10 slow downs from 40 mph and then 2-3 more slow downs from 45 mph, all without ever coming to a stop. Maybe it is living in California, but roads are simply too crowded to ever have that much empty road available. I do plan to continue the bed-in process and see if I can improve their performance before I buy new pads. In further reading, it does appear that ceramic pads are great for low-noise and low-dust, but their coefficient of friction is not as high as other pad types. Thanks for the suggestions.

This is what Moss provides:
Basic Bed-In Procedure
During pad or disc break-in, do not come to a complete stop, so plan where and when you do this procedure with care and concern for yourself and the safety of others. Please Note - If you come to a complete stop before the break-in process is completed there is the chance for non-uniform pad material transfer or pad imprinting to take place and the results will be an irritating vibration during braking.
1. After installing new disc rotors and/or brake pads, perform eight to ten slow downs applying moderate pressure from approximately 30 – 40 MPH (50 -- 60 kph) without coming to a stop.
2. Make an additional two to three slow downs applying heavy pressure from approximately 40 – 45 MPH (60 - 70 kph) without coming to a stop.
3. DO NOT DRAG BRAKES!
4. Allow at least 15 minutes for brake system to cool down.
5. During cool down, while the car is at rest, DO NOT APPLY THE BRAKES! If you do, material will be transferred from the pads to the rotor, and the results will be an irritating vibration during braking.
 
I do plan to continue the bed-in process and see if I can improve their performance before I buy new pads.

Good they really have to be heated up during the bedding in
 
shortsguy1 said:
Thanks Glenn for that info. I clearly have a bit more homework to do.

Steve- That is a very good question. I can say I did my best to follow their directions, but they are unclear and difficult to follow (see below) . They say that you cannot come to a stop during the break-in process, but that you should cool the brakes with the car at rest. I found the inconsistency confusing. I also had trouble finding a road where you can do 8-10 slow downs from 40 mph and then 2-3 more slow downs from 45 mph, all without ever coming to a stop. Maybe it is living in California, but roads are simply too crowded to ever have that much empty road available. I do plan to continue the bed-in process and see if I can improve their performance before I buy new pads. In further reading, it does appear that ceramic pads are great for low-noise and low-dust, but their coefficient of friction is not as high as other pad types. Thanks for the suggestions.

This is what Moss provides:
Basic Bed-In Procedure
During pad or disc break-in, do not come to a complete stop, so plan where and when you do this procedure with care and concern for yourself and the safety of others. Please Note - If you come to a complete stop before the break-in process is completed there is the chance for non-uniform pad material transfer or pad imprinting to take place and the results will be an irritating vibration during braking.
1. After installing new disc rotors and/or brake pads, perform eight to ten slow downs applying moderate pressure from approximately 30 – 40 MPH (50 -- 60 kph) without coming to a stop.
2. Make an additional two to three slow downs applying heavy pressure from approximately 40 – 45 MPH (60 - 70 kph) without coming to a stop.
3. DO NOT DRAG BRAKES!
4. Allow at least 15 minutes for brake system to cool down.
5. During cool down, while the car is at rest, DO NOT APPLY THE BRAKES! If you do, material will be transferred from the pads to the rotor, and the results will be an irritating vibration during braking.
Click to expand...


StopTech has a good description with explanations - I followed that:
https://tinyurl.com/oqmydzh

Including the phenomenon of "Green Fade" which may be the point you're at.
 
Thanks everyone for those suggestions and directions. I will keep at it to see if I can get these ceramic pads from moss to bed-in. If not, my current plan is to go with EBC yellow pads. Of the EBC pads, the yellow ones supposedly have the highest coefficient of friction when cold (if you trust their website). Public comments seem to support that claim. The apparently have pretty high dust levels, but I would rather my car stop cold and have dirty wheels than the opposite.

A few of you may recall that I am mostly trying to get this car safe for my mom and sister to drive, so I don't want the vehicle to require a heavy foot if at all possible. If ever I can get a garage built at my house in San Luis Obispo, perhaps the car will come live with me someday. But for the foreseeable future, it resides with my family, and I am doing everything I can to get it as safe and reliable for them. Thanks again.
 
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