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Brake Pedal Feel

Gearhead_Garage

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My BJ8 came (to me) with no booster and BJ7 master cylinder so it should stop just like a BJ7 without a booster. My car stops ok when significant pedal pressure is applied but the pedal is a bit soft and requires about 1/3 travel before I get significant stopping power. Front to rear bias seems fine. The pads and shoes are new and look like plain old organic. (I didn't buy them but I think they came from Moss). I will pull them out when I get a chance and report what they are.

All components are new or rebuilt and appear to be in good condition. It stops straight with no pulling. I recently bled the entire system and adjusted the rear shoes. That made it slightly better but not good enough. If I stomp on the pedal I cannot lock up the brakes so I believe they should be better in both pedal feel (I would like a harder pedal) and stopping ability.

I have read the pad recommendations (Moss ceramic, semi-metallic, and Porterfields). It seems to me that better pads might stop better but that will not help the pedal travel or mushy feel. Any thoughts?
 

HealeyRick

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I suspect what's happening is due to the use of the BJ7 master cylinder. The BJ8 uses a Girling Type 16 caliper which has larger caliper pistons than the BJ7's Type 14. The later calipers would require more brake fluid to activate than the earlier ones and the BJ7 master cylinder would have to travel further to provide it. Not sure what the cure is, although some have removed their BJ8 servos and kept the BJ8 master cylinder, but report a higher brake pedal effort. Some say it's too high, others report it's manageable. Good article on the different calipers here: https://www.acmefluid.com.au/larry/brakes.pdf
 
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Gearhead_Garage

Gearhead_Garage

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That is very interesting. According to that article, very early BJ8s like mine had smaller calipers so in fact the bj7 master may be original equipment.

I am going to get the car in the air and do a complete inventory of installed parts to see what is what.

With a BJ8 phase 1 it is easy to end up with mix and match parts because it is half BJ7.
 

steveg

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That is very interesting. According to that article, very early BJ8s like mine had smaller calipers so in fact the bj7 master may be original equipment.

I am going to get the car in the air and do a complete inventory of installed parts to see what is what.

With a BJ8 phase 1 it is easy to end up with mix and match parts because it is half BJ7.

A friend is successfully running the DW kit: an early 70s Triumph caliper I believe. It uses the larger late BJ8 pad with the smaller 3.25" bolt centers and older, thinner rotor design. Pedal feel is fine with the .625" m/c from the BJ7. You will not have to replace your m/c.

A better setup would be the DW 3.5" bracket with 4 piston Volvo or Toyota caliper and thicker late BJ8 rotor.

I do not know, however, if the 3.5" bracket will work with the older stub axle. DW would have to verify this. Perhaps one of the Brit forum folks could call them on the phone and find this out. Their site only says it works with their replacement stub axle.
 

steveg

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I suspect what's happening is due to the use of the BJ7 master cylinder. The BJ8 uses a Girling Type 16 caliper which has larger caliper pistons than the BJ7's Type 14. The later calipers would require more brake fluid to activate than the earlier ones and the BJ7 master cylinder would have to travel further to provide it. Not sure what the cure is, although some have removed their BJ8 servos and kept the BJ8 master cylinder, but report a higher brake pedal effort. Some say it's too high, others report it's manageable. Good article on the different calipers here: https://www.acmefluid.com.au/larry/brakes.pdf

The article describes a balance-bar pedal box modification to implement a dual-circuit system with proportioning between front and rear discs. IMO a simpler setup is to use the Fiat 124-131 .75" dual circuit master cylinder adding a proportioning valve into the rear circuit. A friend is working on a bolt-on valve with rear hose for the axle, requiring no tubing flaring.

After one of our members had a near head-on colision in New Zealand due to a total brake failure, some of us came away impressed with the need for dual braking systems.
 
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Gearhead_Garage

Gearhead_Garage

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I am not against modifying the car to make it more safe or drivable but my preference is always to optimize the original system so that it drives as much like a Healey as possible. Some weak points like cooling and passenger heat have been addressed.
I have not heard complaints about the Healey brakes so I intend to tweak them until they work as well as possible. Then, if they are not good enough I will think about mods. Since I am new to Healeys I was trying to get some feedback as to how much better my brakes should be so I know what to expect.
 

HealeyRick

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Don't know if you're using silicone brake fluid, but I've noticed it produces a softer pedal than standard fluid. If you jack up the rear and spin the rear tires with the car in neutral, can you lock up the rear brakes? I have a BJ7 with a stock brake system (no servo) except for stainless hoses and uprated front pads. I have a high pedal and good stopping power. Were your brake hoses replaced?
 

HealeyRick

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I agree the stainless steel brake lines will give a firmer feel, but they probably won't cure the brake travel problem. I suppose if the hoses had deteriorated so much in the interior that they weren't getting sufficient fluid through, that could cause having to press further down on the pedal, but I'm thinking if all the components are the correct ones for the car, then I have to think the friction surfaces are too far away from the brake disc or drum. I know we had a discussion of some of the Moss brake linings appearing thinner than the originals and wonder if so, this may be part of the issue. I'd suggest checking the rear brake adjustment again.
 
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Gearhead_Garage

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Using regular Dot 3 or 4 fluid. I've had old line British car guys tell me Castrol LMA or nothing but I am not running that. Brake lines are brand new rubber type. I would have preferred steel braided but as a cheap bastard, I hate to replace brand new parts that I just paid for. I will study it more when I return from Florida.
 

steveg

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I agree the stainless steel brake lines will give a firmer feel, but they probably won't cure the brake travel problem. I suppose if the hoses had deteriorated so much in the interior that they weren't getting sufficient fluid through, that could cause having to press further down on the pedal, but I'm thinking if all the components are the correct ones for the car, then I have to think the friction surfaces are too far away from the brake disc or drum. I know we had a discussion of some of the Moss brake linings appearing thinner than the originals and wonder if so, this may be part of the issue. I'd suggest checking the rear brake adjustment again.

Agree the problem could be in the rear adjustment. The front discs would back off only to the amount of runout of the rotor, but the rears, if adjusted too loosely, would back off as far as the springs would pull them.
 
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Switch to braided lines like Goodridge. They will provide a stiffer pedal.

I experienced that as well. Used the Moss DOT rated hoses which are less expensive than Goodridge.

I agree the stainless steel brake lines will give a firmer feel, but they probably won't cure the brake travel problem. I suppose if the hoses had deteriorated so much in the interior that they weren't getting sufficient fluid through, that could cause having to press further down on the pedal, but I'm thinking if all the components are the correct ones for the car, then I have to think the friction surfaces are too far away from the brake disc or drum. I know we had a discussion of some of the Moss brake linings appearing thinner than the originals and wonder if so, this may be part of the issue. I'd suggest checking the rear brake adjustment again.
When I still had the front drum brakes fitted to my BN6, I could always maintain a rock-hard pedal feel, with hardly more than an inch (1") of pedal travel__truley confidence inspiring retardation! Only once ever, did I fade those brakes, accelerating DOWN Steiner Street, towards Lombard while doing my best interpretation of McQueen's Frank Bulitt! By the time I reached San Francisco's Cow Hollow Motor Inn and parked in the garage, they were smoking hot (and the garage still stunk an hour later when I left...).

But I digress ;)

After changing to 3000 MKI front discs, and using the correct non-servo master cylinder, I was never able to get that same solid pedal feel. The brakes were bled numerous times (it can take a while to get all the air out of a totally new system) and of course, all the rubber hoses were replaced. Just never felt as good, and I adapted to apply the brakes with two-pumps every time I wanted to slow or stop.

Car was like that for years, including a complete re-tube with stainless pipes and more fresh rubber hoses. First press of the pedal always felt as if it went halfway to the floor and the instantaneous second pump felt like it only went a quarter of the way down. I just got used to it, and let my mind worry about other aspects of Healey driving...

Not all that long ago, maybe last year, while doing a routine brake fluid purge, I couldn't get any fluid out of the rear brakes with my 20 psi or so bleeder. If the pedal was pushed down, fluid would come out the bleeder(s). So I closed the bleeder, stomped the pedal and quickly tried to rotate a rear wheel, and as expected, the shoes are still tight enough to the drum to prevent me rotating it by hand (there was no indication of this driving the car before doing the brake fluid purge). I decided to order new hoses, because if one (1) is bad...

Since the last time I bought rubber hoses, Moss now lists the stainless variety to include the 2-seaters, so I got them instead (already had one on the clutch circuit). Wow, I got my pedal back! Now I'm back to a single push on the pedal, any time I apply the brakes.

So, all that, just to say I agree with you; the s/s hoses (mine sourced from Moss) really did make a noticeable difference in feel. Still have slightly more pedal travel than I did with the well-adjusted drum brakes, but certainly acceptable now.

Carry on... :cheers:
 

bdcvg

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I just test drove My car Fri. for about 40 mins. Fresh resto from Four in Tune that included a conversion from stock BJ8 power servo to BJ7 manual with the Goodridge lines. The brakes are very firm, pedal travel is reduced and instead of the "all or nothing" power servo , I was able to modulate the amount of braking. I have converted My other cars to braided lines after doing My Subaru about 5 years ago and in each car the pedal stiffness improved and reduced travel. The rubber hoses expand under pressure creating a little "mush" and increase pedal travel. Think about how little fluid is really in the system, a little flex can produce a lot of "mush".
 

Bob_Spidell

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Using regular Dot 3 or 4 fluid. I've had old line British car guys tell me Castrol LMA or nothing but I am not running that. Brake lines are brand new rubber type. I would have preferred steel braided but as a cheap bastard, I hate to replace brand new parts that I just paid for. I will study it more when I return from Florida.

We put Castrol LMA in our BN2 and it gelled after a couple years of not being driven (much). Flushed the system and put more LMA in and the MC started to leak (not saying the fluid had anything to do with it, but ...). Bought some really expensive German-made stuff--think it's what BMW uses--and no problems for several years now.
 

steveg

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We put Castrol LMA in our BN2 and it gelled after a couple years of not being driven (much). Flushed the system and put more LMA in and the MC started to leak (not saying the fluid had anything to do with it, but ...). Bought some really expensive German-made stuff--think it's what BMW uses--and no problems for several years now.

FWIW - I've been using the NAPA DOT 4 which is available in quarts for several years now with no problems. My understanding is the LMA-only-thing-due-to-the-rubber is 25 years old at this point.
 

HealeyRick

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Gearhead_Garage

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Just ordered some stainless hoses. We'll give that a try. Thanks for advice.
 
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