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Thread: Towards better brake performance....

Forum to discuss Austin Healey Sports Cars

  1. #1
    Yoda Michael Oritt's Avatar
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    Towards better brake performance....

    Whether due to aging of the driver or brake materials--or both--it appears that lately I must exert a lot of pedal pressure to get what seems like less braking response. I know this is a very subjective statement and I have no way of quantifying the braking but I have been driving my car for 20 years and am sure that it just isn't stopping the way it used to.

    Here is some background information:

    1. I just, as in last week, replaced the brake hoses front and rear with a set of braided stainless hoses obtained from Old Phartz. I used him as opposed to Moss or other suppliers because I have BT7 front discs and stock 100 rears which take a different rear hose than the 6-cylinder cars, and he was willing to "Mix and Match" the later front hoses and original rear hose, whereas Moss only wanted to sell me two kits. It took a bit longer to obtain them than originally promised but what came in was great--actually about 3/4" more in length which made installation a bit easier.

    2. I also just--last week--rebuilt the master cylinder and installed new rear wheel cylinders, and in the process flushed the hydraulic system entirely and refilled with Wilwood 570 high-temp Dot 4 fluid. The system is positively bled and the pedal is nice and hard and where it should be with just a bit of free movement.

    3. The front pads and rear shoes have been replaced within the last twelve months and probably have less than 3K miles on them. Nevertheless the rotors seem to have a "glazed" appearance and the rear shoes have definitely been exposed to some slight leakage of diff oil, though not enough to saturate them.
    Shoes and drums were cleaned following cylinder replacement.

    4. I have a restrictor valve on the line to the rear brakes which, when turned down all the way, reduces fluid flow to approximately 60% of wide open. I have the valve turned all the way to reduced-flow in order to maximize fluid delivery/pressure to the front brakes as they do most of the work. There is a definite falling off in brake performance as the valve is opened.

    5. The rear brakes are properly adjusted and the parking brake is functional when engaged.

    6. I can, with extreme pedal pressure, lock the front brakes with little or no side-to-side pulling.

    7. Tires are Michelin XAS with plenty of tread and 30 psi all around.

    I just lost my lease to a warehouse space I have been renting and must clear out in a few weeks, so for that and other reasons I am not able to undertake any big project such as putting in a servo or replacing the front rotors with some racing stuff or rear brakes with discs, etc. However I am able to put on new front pads and rear shoes, and perhaps have the front rotors turned if need be. So I guess what I am looking for is some recommendations on what materials I might use to give good braking with reasonable pedal effort. I do my racing on a track in my other cars and am not looking to equip the Healey with rock hard pads/shoes. I merely want to improve the car's braking so I do not have to stand on the pedal to get the car to stop.

    Best--Michael Oritt
    1954 Austin-Healey 100 Le Mans
    1959 Elva MK IV Sports Racer
    1961 Ginetta G4

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    Yoda steveg's Avatar
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    Re: Towards better brake performance....

    Michael,
    You might consider new rotors ($26 ea) and the Moss ceramic pads ($38/set). IMO these and a little more adjustment of the proportioning valve will get you a better pedal effort.

    A friend just installed the ceramics on his newly restored BN2 and is very happy with the pedal effort and lack of squealing.
    Steve Gerow
    Altadena, CA, USA
    Maker of most complete Big Healey rear disc kit
    Check out my galleries:
    http://www.pbase.com/stevegerow


  3. #3
    Yoda HealeyRick's Avatar
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    Re: Towards better brake performance....

    Mike,

    I hesitate to suggest this as you are probably familiar with this from racing, but did you bed in your brakes? https://www.zeckhausen.com/catalog/i...Path=6446_6443 I'm surprised what a difference it made on my car after putting the Toyota front calipers on. Not easy to find a place on the street around here where you can do ten 60-0 stops in a row without getting rear-ended.
    Rick

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    Yoda John Turney's Avatar
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    Re: Towards better brake performance....

    Did you change the pad material from what you had before?
    John, BN4

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    Jedi Warrior red57's Avatar
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    Re: Towards better brake performance....

    I don't know what bore master cylinder you have but you might try a smaller bore master. Will result in more hydraulic pressure in the calipers/wheel cylinders for the same pedal pressure, downside is more pedal travel too.
    Pegasus has a pretty good selection if you are still using Girlings.

    Are the 100 rear cylinders a different size than the 3000? If they are the same size, I don't understand why you have a proportioning valve because what you describe is basically a stock 6 cylinder set up and they didn't have proportioning valves stock. I never had one until I went to rear discs.

    Other than cylinder size, you might call Porterfield and see what they suggest - they have a street version of the R4 carbon kevlar and it is a sweet pad material IMO (and they can line a set of shoes with it too).

    Dave

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    Jedi Knight Bob Claffie's Avatar
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    Re: Towards better brake performance....

    I once wanted to increase my braking for cheap money. I put in the absolutely softest pads I could find ( a NAPA pad for about $10.00) and ended up with a sweet pedal at the expense of significantly additional wear. This was on a Spitfire but similar front disc rear drum set-up.
    Thank goodness the MG is finally gone, replaced by another Corvette

  7. #7
    Yoda steveg's Avatar
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    Re: Towards better brake performance....

    The disc-front cars have smaller rear brake slave cylinders than the all-drum cars. This gives proportioning in lieu of the valve.
    Last edited by steveg; 09-30-2019 at 12:39 AM.
    Steve Gerow
    Altadena, CA, USA
    Maker of most complete Big Healey rear disc kit
    Check out my galleries:
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  8. #8
    Yoda Michael Oritt's Avatar
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    Re: Towards better brake performance....

    Thanks all for the input and I will probably pursue Steve's suggestion: "You might consider new rotors ($26 ea) and the Moss ceramic pads ($38/set)."

    Best--Michael Oritt
    1954 Austin-Healey 100 Le Mans
    1959 Elva MK IV Sports Racer
    1961 Ginetta G4

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    Re: Towards better brake performance....

    FWIW, I bought a pair of rotors on sale from Moss a few years ago; they were Brembo (at least, they came in a 'Brembo' box). I was pleased.

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    Re: Towards better brake performance....

    It was 40 years between Healey ownerships for me, and when I test drove a couple of Healeys before buying my '60 BN7 a number of years I felt I wasn't getting sufficient braking. My daily driver has four-pot Brembos though marked Porsche, so I was used to good braking. After purchasing my car, I bought the brake servo kit sold by Victoria British and installed it. Unfortunately, I also installed the later larger diameter master cylinder that produced an excessively firm pedal. Someone on the Forum, likely Steve G, promptly told me that I should use the standard master cylinder. I did that and have a very nice pedal, albeit I had also upgraded the flexible brake lines front and rear, the rear brakes entirely except for the drums and the front brake cylinders in the process. Putting a servo on a Series 1 car that apparently never came fitted with servos was no picnic, however.
    Owner of a 1960 BN7 with Toyota 5 speed and a '92 Porsche 968 coupe. Former owner '62 Jaguar MK2, MG-TF brought back from military service in Italy 1958, '61 Healey BT7, pre-A Porsche 356, and a Porsche 944.

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    Re: Towards better brake performance....

    Quote Originally Posted by RDKeysor View Post
    ... Putting a servo on a Series 1 car that apparently never came fitted with servos was no picnic, however.
    Presumably, it didn't have a mounting bracket pre-installed?

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    Yoda steveg's Avatar
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    Re: Towards better brake performance....

    Just spoke to David Nock who's done lots of conversions of 100s. Points:
    --smaller MC not available for 100 - he always uses the stock MC - says they work fine
    --Not necessary to swap out rear wheel cylinders - says the discs work fine even with the early BN1 larger rear wheel cylinders
    --Excessive pedal pressure is due to something other than the size of the MC

    Queried my friend with the 100 - he replied the pedal pressure with the ceramic pads was no different from previous pads, but he had never had a pedal pressure problem - only loud squealing, which the ceramics permanently banished.
    Steve Gerow
    Altadena, CA, USA
    Maker of most complete Big Healey rear disc kit
    Check out my galleries:
    http://www.pbase.com/stevegerow


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  14. #13
    Yoda Michael Oritt's Avatar
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    Re: Towards better brake performance....

    I ordered new front rotors and semi-metallic pads and rear shoes from MM today. Unfortunately I will not be able to install till next week but will report back when done.
    Given that everything worked very well for many years with present/original) master and rear wheel cylinder sizes I don't see why I would need to make any changes there.
    Thanks all for the input and suggestions.

    Best--Michael Oritt
    1954 Austin-Healey 100 Le Mans
    1959 Elva MK IV Sports Racer
    1961 Ginetta G4

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    Re: Towards better brake performance....

    No, it didn't have the mounting bracket installed. The correct mounting angle is very much stressed in the servo instructions, and I eventually used a couple of washers to shim mine to where i thought it needed to be. I don't know at what point Healey began offering the cars with the servo installed.
    Owner of a 1960 BN7 with Toyota 5 speed and a '92 Porsche 968 coupe. Former owner '62 Jaguar MK2, MG-TF brought back from military service in Italy 1958, '61 Healey BT7, pre-A Porsche 356, and a Porsche 944.

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    Jedi Knight Rob Glasgow's Avatar
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    Re: Towards better brake performance....

    I too am not satisfied with the braking of my BT7. I also must add that I am very gentle on brakes, slowing and using the brakes gently in normal driving. On all the cars I've owned, the brake pads last 100,000 plus. Although I've driven the Healey for 56 years and had not given much thought to the system, I don't think I've ever been able to lock the front brakes in a hard stop. The rears will lock but not the fronts. I've rebuilt all the components in the past several years, but I still have the orinial front rotors. Since there is no pulsing when applying the brakes, I assumed they were fine.
    But after reading the above comments about replacing the rotors, I'm considering that as a next step. Has anyone experienced a stopping improvement by just changing the rotors?
    Rob Glasgow

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    Re: Towards better brake performance....

    Quote Originally Posted by Rob Glasgow View Post
    ... Has anyone experienced a stopping improvement by just changing the rotors?
    Not that I can tell (but I usually change pads when I change rotors). I have noticed improvements, for example my favorite local parts house guy--who sadly drove his Harley off the 280/101 overpass in San Jose--recommended some Ferrodo pads which had significantly more stopping power than the Bendix organics I was running.

    FWIW, drilled, slotted, vented rotors are overkill on a street Healey (IMO; and I've heard the drilled ones have a tendency to crack). The last rotors I got from Moss on sale were Brembo brand, which is a quality name.

  18. #17
    Yoda HealeyRick's Avatar
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    Re: Towards better brake performance....

    I suspect the ability for the rear brakes to lock up has more to do with weight transfer removing the weight from the rear tires rather than the efficacy of the rear brakes. Chris Dimmock asked on the team net forum recently if anyone had ever replaced their rear brake shoes because they had worn out and very few had. That would lead to the conclusion that the front brakes in a Healey are doing the most of the work Probably the easiest way to increase braking performance without going to the expense of changing to larger calipers and bigger rotors is carefully picking replacement brake pads designed fur street use. Stay away from race pads, they require extra heat to work effectively and street stopping distances will suffer.
    Rick

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    Yoda John Turney's Avatar
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    Re: Towards better brake performance....

    One thing to keep in mind if you can no longer lock the brakes: If you fit stickier tires than the old Road Speed tires, it requires more braking to overcome the increased tire grip.
    John, BN4

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    Jedi Knight Rob Glasgow's Avatar
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    Re: Towards better brake performance....

    John, good point but I have 13 year old 165/80 Kumos so they're beyond the sticky phase. Santa's says he bring me some new wheels and tires. I can't wait.
    Rob Glasgow

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    Jedi Knight Rob Glasgow's Avatar
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    Re: Towards better brake performance....

    Bob, what model Healey do you have? I haven't been able to locate Ferodo pads to fit my BT7. Only found ones that fit the BJ8. Same situation with EBC Green Stuff pads.
    Rob Glasgow

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