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Brake servo

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K

kcolas

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After starting an investigation on hot (smoking once) front wheels, I noticed the bearing grease caps loose--meaning I can pull them out easily, and the grease residue aroung the hub is scorched. I started this on another post and got plan to check the pistons to see if they stick, as well as repack the bearings, but then thinking about related stuff, I realised the brakes have never seemed to be overly powerful, the pedal going nearly to the floor, but stopping the car OK.
Is there a way to tell if the servo is functioning properly? The reason I suspect this is that I also had bouts of smoke at times --never consistant enough to pin down, and on a previous thread someone said white smoke is a sign of a bad servo. Because I didn't understand, I failed to ask right away and tried to figure it out with the manual and by the connections in the brake system. Anyone willing to offer a basic lesson in other than "the king's english?"
wink.gif

Kirby
 
The grease cap covers the smaller outer bearings and there is another much larger inner bearing that you access by pulling the hub. You may have a dry inner bearing which heated up the hub to "smoking hot". If the servo is burning brake fluid your brake fluid level would be going down. Is this happening? There is an article on Servos and Wheel bearings at Jim Werners site: https://hometown.aol.com/bgahc/jimwerner.html but a Factory workshop manual is advised for details of assembly/disassembly.
cheers.gif
John
 
John,
Thanks for the leads. Both seem to be great sources and led to further good threads. Looks like I'll be spending some time getting to know the brakes.
Cheers
Kirby
 
The white smoke you get could be caused by brake fluid leaking into the vacuum chamber. When you hit the brakes the engine draws a vacuum to assist in braking. It also sucks up some fluid and burns it. Your brake fluid should be low if this is happening.

SB
 
Thanks to all for the help and ideas. I just got the Norm Nock tech papers and have done lots of research. I think I'll attack this one step at a time.First the wheel bearings get refreshed. Next I think the brakes get a thorough inspection and fluid change. Still not sure about the servo, but the more I read the cloer I'm getting to understanding it. I don't think its working--not locking up, but just no help. Randy (Cook?) at Healeymaster did the resto and warned me about letting the seals get dry from not driving it enough. Any quick checks to see if it is even functioning?
Kirby
 
I had the local Jag guy check the brake sytem and he found the bearings shot and the servo is not working. He is at a loss to find a repair kit so I'm considering having it sent to get rebuilt or get the kit myself. I remember seeing a thread about the correct lubricant for the plunger and that being fairly important. I don't want to do more harm than good, but after the bill for replacing a couple of wheel bearings, I'm going to have to get dirty...help.
kirby
 
On the servo rebuild. Sunbeam used the girling servo as well. Both 5 and 7" were used. I have rebuilt as well as had one done by a highly reputable builder.Make sure that whoever does this for you can test properly on a testing machine. When I had mine done it was satisfaction regardless even though I was suppliing the rebuild kit.Well it took 3 times to my satisfaction and he never even saw the car. You can almost breath heavy on the pedal and stop. Sure learned to remove it fast.It makes the one I did in the 65 tiger feel heavy even though I do know it is working.They do need the equipment to set the return spring to exact specs.Also they will check alignment of the piston to the rod. This is important as well as a good piston seal and the right lubricant.
You may also want to check out the part department at a volvo dealer for a kit as volvo used girling servos. May be you will luck out and find a super parts person.
$450 US sounds very pricey as it was only 145.CDN plus my kit.

[ 12-27-2002: Message edited by: thegoodbeamer ]</p>
 
Thanks Mike.
I talked with David Nock and he said a rebuild on the servo was 450$(USD) {option 1} It seems a new one of the Lockheed types is a little less than that{option 2}. VB and Moss have rebuild kits for about 80${option 3}, but David said that owner rebuilds are not usually successful. Does anyone have any experience here? I found an interesting article and source for the type of lubricant that can help this problem, I think. Any opinions on these options?
 
Thanks Chuck for the good info concerning your rebuilds. I haven't heard of a test bench, but it seems that with a measuable vacuum source, you could operate it on a bench. I'll check the closest repair shop to see if he has done it. In shecking the hoses this afternoon, I found a crack in the vacuum hose close to the intake manifold fitting- I have some re checking to do...
Kirby
 
There is another option available, too, and that is to revert back to a non-servo operation. If you install a pre-servo brake master cylinder and connect it up right it will perform similar to a pre-servo assisted Healey. Brakes will be OK, but not as good as servo-assisted, though. I don't necessarily recommend this route, but it will work and will be much less dollars. Stever
 
I talked to David Nock about the possibility of a successful rebuild and he laughed. He did say that his was "only" $350 so that makes it less than a new lockheed unit and bracket. The brakes just don't seem that bad.....That may be because of the smokey exhaust problem, though
smile.gif

Kirby


this space reserved for photo when I figure out the signature thingy...
 
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