Brake line query

[ramblerdan]

Hello

Found some relevant threads in the archives but can't post to them, hence the new thread.

I'm planning to replace the master cylinder and probably most everything else. Have done plenty of brake work on American cars but never metric. One post says the Amphi uses "bubble flare" line termination, as opposed to the 45° double-flare I'm familiar with. Before I buy a "bubble" flaring tool (twice the price of a conventional metric double-flaring tool), can someone verify this?

Also, I saw in a thread about converting to a double-chamber master cylinder (http://www.amphicar770.com/amphicar...cussion/20290-dual-brake-master-cylinder.html) someone mentioned using 1/4" tubing. This seems strange to me to see 1/4" line used on what I assume is an all-metric car.

I have wheel cylinders and flexible lines (as well as shoes and hardware) from Gordon, so the only thing I need to buy is solid line, which I figured I could buy locally at lower cost. Could someone kindly tell me what size line I need, and whether I should specify fittings specific to a "bubble" flare?

Thanks!

 

[ramblerdan]

Follow-up

Brake job complete. Replaced everything but the shoes and drums. I used all pre-bent lines from Gordon Imports except for the long line from the rear splitter to the double-female union near the front firewall. That one I had to cut and flare myself; the local NAPA had hard line with the appropriate fittings and a bubble-flaring tool.

A few observations:

1) It seems that whoever designed the front brakes wasn't talking to the person who designed the steering knuckle. The clearance between the bleeder nipple and the knuckle was so tight on this car that I destroyed the dust covers removing them and could barely get thin-walled polyester tubing over the nipples to bleed. Also, the head of one of the bolts that holds the lower front wheel cylinder in place was so close to a protuberance that a normal 14mm box-end wrench wouldn't fit over it, and naturally a socket was out of the question because of the steering knuckle. I had to grind down a box-end wrench to make its annulus super thin, which did the trick. Fortunately the replacement bolts I used have 13mm heads, so no problem next time (of course I'm hoping there won't be a next time).

I'm told that this problem can be overcome by rotating the backing plate (held by eight screws) so that the top wheel cylinder is tilted toward the rear of the car. This requires removing the hub, which I haven't decided to take on yet because it requires a puller. Every other non-driven wheel hub I've worked on in the past (American cars) just pops off by hand, and I'm a little worried about disturbing the rear dust seal and properly torquing the assembly afterward. Eventually the bearings will have to be repacked or replaced, so will have to do that eventually, and will rotate the backing plates at the same time.

2) The brake-line hold-down clamp closest to the reservoir is in under a corner of the gas tank! I had to empty the tank and undo the mounting band on that side to get at the clamp and replace the line. I'm told that one can just pry the existing clamp to allow the old one to be slid out and a new one put in its place, but I've already replaced it by tilting the tank.

3) The reservoir nipple is quite large (about the o.d. of fuel line i.d.), which made connecting it to the thin brake line with a short length of fuel hose a bit of a challenge. Gordon sells has a dual-ID hose for this.

4) The front flexible lines attaches to the both with banjo bolts and hollow bolts, rather than a short length of hard line between the body and flex hose, as used on the rear wheels. I'm not happy with this design at all, as the placement of the the threads, once tightened, didn't orient the banjo flush with the mounting point on the body, so the flexible line, especially on the driver's side, is twisted to mate with the body. Those lines are certainly designed to bend, but I don't know how much torque they can tolerate in the long run.

5) The front wheel cylinder bleeder nipples are on the bottom cylinder. Since air bubbles rise, it would have made more sense IMO to run the flex hose to the bottom cylinder and put the bleeder on the top one. As for the arrangements of the return springs, don't get me started! How much would it have taken to design them to fit on the outside of the shoes, rather than the inside?

Hope this info helps someone else doing the job someday.

 

[DavidC]

Follow-up

All cars I've seen have backplate arranged on front hub so access is good,
certainly the factory were doing that by 1965.

No puller needed for front hub. You do need a quality one for the rear
hubs.

Front brake hoses are fine, you can adjust out that twist in most cases.

Hose goes to top so it's less likely to be caught in water, pressure
bleeding means it's no problem.

Manual shoes how to fit those springs, it's much easier the second time !
They have to be on the back so they hold the shoes against the backplate.



David C in the UK



One tip, water prop driveshafts to transmission have special M8 star bolts
which can get damaged where people use an Allen key on them. These star
bolts were also used to hold the backplate to rear hub on earlier cars, swop
them for ordinary hex head and you have some spare star bolts for the prop
driveshafts.





From: ramblerdan [mailto:]
Sent: 08 July 2010 21:14
To: david@manbus.com
Subject: RE: [General Amphicar Discussion-t-20778] Follow-up



Brake job complete. Replaced everything but the shoes and drums. I used all
pre-bent lines from Gordon Imports except for the long line from the rear
splitter to the double-female union near the front firewall. That one I had
to cut and flare myself; the local NAPA had hard line with the appropriate
fittings and a bubble-flaring tool.

A few observations:

1) It seems that whoever designed the front brakes wasn't talking to the
person who designed the steering knuckle. The clearance between the bleeder
nipple and the knuckle was so tight on this car that I destroyed the dust
covers removing them and could barely get thin-walled polyester tubing over
the nipples to bleed. Also, the head of one of the bolts that holds the
lower front wheel cylinder in place was so close to a protuberance that a
normal 14mm box-end wrench wouldn't fit over it, and naturally a socket was
out of the question because of the steering knuckle. I had to grind down a
box-end wrench to make its annulus super thin, which did the trick.
Fortunately the replacement bolts I used have 13mm heads, so no problem next
time (of course I'm hoping there won't be a next time).

I'm told that this problem can be overcome by rotating the backing plate
(held by eight screws) so that the top wheel cylinder is tilted toward the
rear of the car. This requires removing the hub, which I haven't decided to
take on yet because it requires a puller. Every other non-driven wheel hub
I've worked on in the past (American cars) just pops off by hand, and I'm a
little worried about disturbing the rear dust seal and properly torquing the
assembly afterward. Eventually the bearings will have to be repacked or
replaced, so will have to do that eventually, and will rotate the backing
plates at the same time.

2) The brake-line hold-down clamp closest to the reservoir is in under a
corner of the gas tank! I had to empty the tank and undo the mounting band
on that side to get at the clamp and replace the line. I'm told that one can
just pry the existing clamp to allow the old one to be slid out and a new
one put in its place, but I've already replaced it by tilting the tank.

3) The reservoir nipple is quite large (about the o.d. of fuel line i.d.),
which made connecting it to the thin brake line with a short length of fuel
hose a bit of a challenge. Gordon sells has a dual-ID hose for this.

4) The front flexible lines attaches to the both with banjo bolts and hollow
bolts, rather than a short length of hard line between the body and flex
hose, as used on the rear wheels. I'm not happy with this design at all, as
the placement of the the threads, once tightened, didn't orient the banjo
flush with the mounting point on the body, so the flexible line, especially
on the driver's side, is twisted to mate with the body. Those lines are
certainly designed to bend, but I don't know how much torque they can
tolerate in the long run.

5) The front wheel cylinder bleeder nipples are on the bottom cylinder.
Since air bubbles rise, it would have made more sense IMO to run the flex
hose to the bottom cylinder and put the bleeder on the top one. As for the
arrangements of the return springs, don't get me started! How much would it
have taken to design them to fit on the outside of the shoes, rather than
the inside?

Hope this info helps someone else doing the job someday.

 

[ramblerdan]

Thanks, David.

Great to know that the front hub comes off normally. But how to alleviate twist in the flex line? I can't loosen the threads on either the cylinder or body end without breaking the seal. Add copper washers?

 

[DavidC]

Problem is the replacement hose Gordon sells have the ends crimped on
randomly, the original Ate had them with the threads in line. Sometimes
they align perfectly, sometime not, swopping the ends around can help, some
hoses fit better one side than the other. You're right the seal is the
conical bit copper washers aren't really going to work as there aren't
shoulders.



From: ramblerdan [mailto:]
Sent: 09 July 2010 01:45
To: david@manbus.com
Subject: SPAM-LOW: RE: [General Amphicar Discussion-t-20778] Re: Brake line
query



Thanks, David.

Great to know that the front hub comes off normally. But how to alleviate
twist in the flex line? I can't loosen the threads on either the cylinder or
body end without breaking the seal. Add copper washers?