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67 BJ8 Brakes

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chuck2

Freshman Member
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Having a problem with the brakes locking up after a few miles.
Repaced the master cylinder,adjusted the travel,bled them to get rid of old fluid.If I pump again after locking they free up.I am thinking the servo which was replaced as an lockheed at some time but would like some other opinons.
 
Had a similar problem with a '68 Porsche. Replace ALL the flex lines. WHat happens is they deteriorate from the inside out and when you push the pedal they expand and slowly go back to the smaller size. Seems this is a very common problem on a lot of cars. I would also maybe think about spending the xtra $$ and buying braided lines, they are of better build quality.
 
I had to do my front and rear brakes by installing new front caliper pistons, all new flexible lines, new rear cylinders and one rigid line, and of course, a new parking brake cable. My brakes work fine.

The only thing left for me, if I have problems down the road, is to deal with the brake servo.

What I will do if my servo needs attention is to simply by pass it by creating a new rigid line where the line meets the servo and then complete the connection to the rigid line feeding the rear brakes. I will keep the servo in place and inactive for judging purposes (if I get that far in life).

I have not done this yet and I know the majority will tell you to fix the servo but what I do remember is how the making of Healeys started off not having a servo and only had drum brakes all the way around. Not to mention rebuilding can be a bit pricey.

And I know what I'm bringing up is probably taboo for most (and I remember that being said to me back then).

Judgement call.

PS. I might of jumped ahead a bit and would first definitely try replacing all (3) flexible lines as suggested above. If you've done everything else (as I did) and are still having locking problems, well then, you know where I stand on the subject of the servo, for future.
 
Sounds like the servo to me. If you do a search on this forum you will find discussions about rebuilding at home, versus sending them out, versus replacing them with a non original unit that fits in with some different brackets. Rebuilding usually requires a kit and some fairly special dry lubricant. Not just some stuff you find at the hardware store. The non original replacement works, but does not have the same pedal feel. The professional rebuild is expensive and takes your car off the road for a bit.
 
Legal Bill said:
Sounds like the servo to me. If you do a search on this forum you will find discussions about rebuilding at home, versus sending them out, versus replacing them with a non original unit that fits in with some different brackets. Rebuilding usually requires a kit and some fairly special dry lubricant. Not just some stuff you find at the hardware store. The non original replacement works, but does not have the same pedal feel. The professional rebuild is expensive and takes your car off the road for a bit.
Click to expand...
Power Brake Exchange rebuilds the servos for a little less than$300.00. They work!
 
PKMH

If my memory is correct, there is something different about the master cylinder on a non servo car and the one on a servo car.

Cant't think what, as they are both 7/8 bore but there are different seals, could the braking be effected beyond the fact that you need a heavier foot?

Bob
 
Bob,

When I was following this discussion a while back, I remember asking the one author more details about how he bypassed the servo. He posted a photo of the modification and explained, from his own driving experience, how there was no significant difference in braking power, further adding about the BJ8 servo vs. all drums on the earlier models.

I tend to believe your view, however, about how you would need a heavier foot if bypassing the servo. I cannot recall for sure about differences in seals, but that was probably brought up, too. I just remembered how this whole issue of the servo was intense, and when my time comes to deal with it, I will more likely adopt or at least try the bypassing method to see how the braking behaves.


Interestingly enough, I remember someone who had a look at my BJ8 a while back noticed how the servo is mounted wrong or even "upside down." I would like to see a clear shot of how a servo is mounted to the frame. For all I know, my servo may of been modified for I tend to feel like I am using a heavy foot to brake (but how would I know since I have not driven another Healey to compare?).

BTW and good advice to all: Make sure your parking brake is working perfectly, no matter what.

Paul
 
pkmh said:
Bob,

When I was following this discussion a while back, I remember asking the one author more details about how he bypassed the servo. He posted a photo of the modification and explained, from his own driving experience, how there was no significant difference in braking power, further adding about the BJ8 servo vs. all drums on the earlier models.

I tend to believe your view, however, about how you would need a heavier foot if bypassing the servo. I cannot recall for sure about differences in seals, but that was probably brought up, too. I just remembered how this whole issue of the servo was intense, and when my time comes to deal with it, I will more likely adopt or at least try the bypassing method to see how the braking behaves.


Interestingly enough, I remember someone who had a look at my BJ8 a while back noticed how the servo is mounted wrong or even "upside down." I would like to see a clear shot of how a servo is mounted to the frame. For all I know, my servo may of been modified for I tend to feel like I am using a heavy foot to brake (but how would I know since I have not driven another Healey to compare?).

BTW and good advice to all: Make sure your parking brake is working perfectly, no matter what.

Paul
Click to expand...
I am doing a ground up restoration and have very good photos of the Servo mounting. Send me your PM and I will forward the photos to you. (Sorry, but I don't have the patience to reduce photos for posting to this website).
 
I had the same problem with brakes locking up after I rebuilt my car. I by passed the servo with small rigid line. Brakes work fine, I can't tell any difference. I have bought a new servo for the car but not installed at present.

Marv
 
Thanks Marv about learning how there's no difference with bypassing the servo. I have heard this from others in the past, too.

So far, my brakes are working fine, my parking brake working terrific (at slow speeds, anyway, I can create rear end skidding with the parking brake alone).

I feel somewhat relieved about that. You never know.

Paul
 
My healey currently has the servo bypassed as described above. It requires WAY more pedal pressure to stop. I only did this as a temporary fix while awaiting a new servo to arrive and would not recommend it if you intend to drive the car any distance. Servos can be has fairly cheap on ebay, I paid less than $200 delivered for a new one.
 
If you can't tell the difference in pedal effort required with the servo bypassed, then your car mustn't have the master cylinder intended to be used with the servo; the pedal effort required is MUCH greater!

The early 3000 & MKII models had "optional" servo-assisted brakes, so there were non-assist and assisted versions of the master cylinder (non-assist has a smaller diameter piston & bore).

My own success rate rebuilding servos is about 70% (and probably declining from that number, as the originals servos got older and the repair kits get less reliable, with fewer replacement parts included...).

The cheap servos on Ebay are just that: CHEAP. They don't have all that great of a success rate either, often keeping the brakes applied after lifting your foot off the pedal. And leaking.

My recommendation is (also) to have it professionally rebuilt by a facility that can guarantee testing before it's been returned to you.
 
Seems to me if a fella wanted to bypass his servo he should switch to the non servo master cylinder as well.
 
Thanks for all the views.I finally found the problem which was the servo.
I had it off and the rear cover off but could not get the diaphram off.
proceeded by bypassing for now. this is a lockheed replacment the previous owner put on. It actually looks somewhat new because the irradyte on the unit still stands out. Does any one have instructions for taking one of these units apart?
Chuck
 
I googled the lockheed servo, found a step by step pictorial on the tearing down of this unit. The main boar looked fine but the little boar that is off the main was sludged up from old grease. this little piston seals off the
fresh air inlet and allows the vacuum to assist.when the pressure is released
the return sring pushes the piston back and the vacuum is released.This inturn
takes pressure off the pads.Thanks again for the opinions.
Chuck
 
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