We travel along a path that seems a good idea, in my case I was simply copying the Torana brake booster mount design and adapting it into the Vogue. Each step of the way you make more compromises to make it work in the new location. Each compromise requiring more compromises until the final result becomes very complicated. Having done all the work to get this far we now have a large investment in the design and become reluctant to make changes as the previous time seems "wasted".
It was too cold to go out to my shed so went back over the pile of sketches and drawings, mainly to discard the ones that now confuse the whole design. In the pile was a simpler arrangement to push the booster push rod that had been discarded as the Holden system seemed simpler.
I had also looked at fitting a similar set up in my Rapier project which has many vital parts missing and will also be an improved version when completed. However the pedal assembly that is used in the Rapier makes using the pull rod and bell crank arrangement borrowed from Holden unworkable. So any installation would need to apply brake action through the original push rod off the brake pedal.
A quick trial installation in the Rapier showed that the mount would work and it could fit with the booster about 5 1/2" above the existing mount.
Looking back at the Vogue I thought mounting the booster only 4' above the original clutch slave master cylinder would be better and allow the air intake to fit above the brake master cylinder and give a fairly factory look to everything. As it happened a test fit proved that there was still insufficient space above the Master cylinder for the air intake ducting, but that I could run the intake under it. Moving it up to the previous location an inch higher (5") would make this fit better
Using the existing Vogue brake pedal push rod and angling the operating levers across to the booster directly above it would allow me to put the clutch master back in the original location with access to the filler when required or a remote fluid tank.
Using the existing Vogue brake pedal push rod and angling the operating levers across to the booster directly above it would allow me to put the clutch master back in the original location with access to the filler when required or a remote fluid tank.
I had checked clearances and it would fit but was very tight with the Booster at 4" up, so would be better with it at 5". Here is a picture of the first test fit at 4", the final location having an additional 1" clearance. The clutch slave fits in there quite nicely.
So back to the cardboard engineering :-)
The design was made for the Rapier and worked well, but in that place the booster is directly above the original brake master. The lever design is very simple and can be adjusted to put the booster at whatever height is required. To revert to the original Vogue brake location these levers needed to be on a slant.
When everything is square and vertical it is simple to visualise and draw the set up. However the slant was a bit of a challenge as some vital support parts for the booster seemed to be in the way.
The design was made for the Rapier and worked well, but in that place the booster is directly above the original brake master. The lever design is very simple and can be adjusted to put the booster at whatever height is required. To revert to the original Vogue brake location these levers needed to be on a slant.
When everything is square and vertical it is simple to visualise and draw the set up. However the slant was a bit of a challenge as some vital support parts for the booster seemed to be in the way.
So making a cardboard trial piece to better see what was needed made the answer easy.
A simple bend in the booster support bracket and it all fitted and worked as desired.
The video shows the action and the picture taken from the same angle as the previous cardboard test piece for the pull rod design.
The levers as drawn for the 4" offset.
The first arrangement for the Vogue.
The pivots all have to be parallel.
After making a 3D piece it was apparent that the top pivot point above the booster needs to be offset sideways to clear the booster push rod and boot assembly.
After making a 3D piece it was apparent that the top pivot point above the booster needs to be offset sideways to clear the booster push rod and boot assembly.
A single difficult piece of construction for this design compared with many special pieces in the original.
But I can now leave the original pedal assembly in the car, all the modifications being the bracket and connecting levers in the engine compartment. Much less difficulty overall and able to be reproduced if required.
This is the booster at 4" above the original master.
The Mitsubishi air intake
A month to get to this point. :-)
2nd August:
And 24 hours to finalise the new design.
Some more cardboard engineering templates to mark out the steel for the bracket.
Because the lever system is at about 26.5 degrees to the vertical it becomes confusing trying to draw it all out and not make annoying errors.
There will also be an welding assembly jig to get all these parts in the correct alignment.
I should be able to create the final masterpiece in a couple of leisurely days.
I should be able to create the final masterpiece in a couple of leisurely days.
The up side of all this is I will sell off the surplus Holden Torana parts to compensate me for the time I spent stuffing around with them :-)
11th August 2022
Progressing slowly.
Progressing slowly.
Cardboard engineering again
Plus an assembly jig to hold it while it gets assembled.
Along with some bespoke brain lubricant for the engineer :-)
The multiple angles that everything needs to work on create places where you cannot see the problems until it starts going together.
Getting brave I cut out some parts from 3mm steel.
The multiple angles that everything needs to work on create places where you cannot see the problems until it starts going together.
Getting brave I cut out some parts from 3mm steel.
Did a trial fit after welding it together and adjusting clearances in a few places.
The booster mount plate was drilled for both the Holden and Mitsubishi boosters as I have both available. Mitsubishi parts are cheap and available while the Holden parts now have "Cult followers" prices.
Removed it from the car and did a test fit of both boosters:
First four pictures show the Mitsubishi unit with a Pajero master cylinder. The preferred master cylinder is from the Magna which has a lower profile. The one in the pictures is too high for the Vogue.
First four pictures show the Mitsubishi unit with a Pajero master cylinder. The preferred master cylinder is from the Magna which has a lower profile. The one in the pictures is too high for the Vogue.
These pictures are the Holden Booster:
The Holden fits better and the mount bolts are slightly more convenient.
I modified the bracket to allow access to the Mitsubishi unit and created a future tight spot for the operating levers.
I modified the bracket to allow access to the Mitsubishi unit and created a future tight spot for the operating levers.
Measuring it all again as although the booster is now mounted 5" higher than the original master cylinder the levers to operate it are actually around 7 3/4" inches long because they are on an angle that is around 26.5 degrees. More accurately 5" up and 2 1/2" across. While there are many ways to transfer the movement of the pedal push rod to the movement out to the booster it was easier to make the transfer at the half way point. So the link on the first long lever is connected half way along the 7 3/4" and the secondary lever mid point then connects to this with a short link. As a result the distance down from the top pivot (2") sets the length of this lever. Simple division half the first lever is 3 7/8" so the secondary lever is 2 x 1 7/8" which then sets the bottom pivot point at 2" above the original push rod....Simple as :-)
The short secondary lever is straight and was cut from a piece of 1.25" x .25" strap which is the same as the original brake pedal lever, Strong enough.
The longer primary lever needed to be shaped to go around the booster pushrod boot which is around 2" diameter. I had thought of cutting two pieces of 3mm thick material and going around both sides but the trial piece seemed to "light" for the duty involved (and I have to convince an engineer to sign off on this work) so I made a single piece of 1/4" curved around one side and down the centre to the pedal push rod.
There are clever formulas to work out where to bend so as to allow for the material "growing" as you bend it. There are experimental factors to toss in there as well and my effort was not quite right.
The longer primary lever needed to be shaped to go around the booster pushrod boot which is around 2" diameter. I had thought of cutting two pieces of 3mm thick material and going around both sides but the trial piece seemed to "light" for the duty involved (and I have to convince an engineer to sign off on this work) so I made a single piece of 1/4" curved around one side and down the centre to the pedal push rod.
There are clever formulas to work out where to bend so as to allow for the material "growing" as you bend it. There are experimental factors to toss in there as well and my effort was not quite right.
It is quite difficult to bend a 1" radius for 90 degrees then a tight bend 1/4" radius the other way with the second bend very close to the first. I was about 1/2" to far across and could see that the order I did the bends in would make very little difference, the second bend will move away from the first as you work the metal. To bend 1/4" material requires a fair amount of pressure so I was using my universal shop press to provide the grunt. A couple of pictures of the jigs I used to apply the pressure where it was needed. Bearing in mind that these parts have sideways pressure on then as well and bits can exit the press at high speed with no warning. I managed to move the wider curve closer to the tight bend, then straightened the top end so that the straight parts were parallel. A case of bend it a bit and remove to check, reinsert in press and bend a bit more and check again.
The finished result:
Using one lever only gives more clearance from the clutch slave cylinder.
Doing it this way there is a single primary and secondary lever with the link being two parts on either side. In the diagram the link is located just below the sharp bend. The push rod from the original brake pedal is at the bottom, the push rod for the booster is the top of the lever in blue high light.
Doing it this way there is a single primary and secondary lever with the link being two parts on either side. In the diagram the link is located just below the sharp bend. The push rod from the original brake pedal is at the bottom, the push rod for the booster is the top of the lever in blue high light.
The lower pivot point is on the cross line between the pedal push rod and the link.
There is a clearer picture of the original design a few pictures back in this post, the close clearance to the clutch master cylinder is apparent. What the drawing does not show is that the lower pivot is even closer.
There is a clearer picture of the original design a few pictures back in this post, the close clearance to the clutch master cylinder is apparent. What the drawing does not show is that the lower pivot is even closer.
More pictures:
The levers and link piece
The cut away on the link to give sufficient clearance from the first lever.
Required because the link needed to be in the middle of the first lever.
The connection to the booster
the lower pivot and the link.
Side view with pedal box attached.
From the pedal side The angled levers are very apparent.
So far it looks very successful.
Push the pedal and everything works very smoothly.
Make up some custom pivot pins and a wider bearing length for the top pivot and
Push the pedal and everything works very smoothly.
Make up some custom pivot pins and a wider bearing length for the top pivot and
I am sure that engineering approval will be assured.
The end result is that a readily available (read low cost) power brake set up from a modern vehicle can be installed with the safety benefit of dual circuit brakes.
The bracket will accept both the Holden and Mitsubishi 9 inch boosters with plenty of clearance.
The end result is that a readily available (read low cost) power brake set up from a modern vehicle can be installed with the safety benefit of dual circuit brakes.
The bracket will accept both the Holden and Mitsubishi 9 inch boosters with plenty of clearance.
There are a few slightly smaller vacuum boosters out there but it seems that the 8 or 9 inch size is fairly universal. The sums on reducing the booster diameter also reduce booster effect as taking a few inches off the diameter reduces the effective diaphragm area by a much larger amount. The ratio of the area of a 6" compared to an 8" diameter .
Using the same design I will fabricate a similar mount for my Series 1 Rapier project. This will be much simpler as the levers will be vertical putting the booster directly above the existing master cylinder, This is the same arrangement as the Minx, Husky and I suspect Alpine bodies.
Using the same design I will fabricate a similar mount for my Series 1 Rapier project. This will be much simpler as the levers will be vertical putting the booster directly above the existing master cylinder, This is the same arrangement as the Minx, Husky and I suspect Alpine bodies.
Some almost complete pictures.
The pivot pins are still to be made to replace the 5/16 bolts being used for assembly and movement test purposes.
The pivot pins are still to be made to replace the 5/16 bolts being used for assembly and movement test purposes.
The pedal assembly with the booster and master cylinders attached. The master cylinders will be rebuilt when the rest of the work on the car is complete and all the brake lines are manufactured and in place.
So that pretty much concludes what has become a bit of a saga.
The decision to scrap the original Holden derived pull rod system in favour of a new design was most definitely a better way and can be simply reproduced as required as a bolt in modification, as will the series Minx or Rapier version. This will allow an easily obtained brake booster to be installed with the option of also going to dual circuit brakes.
Now to get on with panel work and paint preparation.
The decision to scrap the original Holden derived pull rod system in favour of a new design was most definitely a better way and can be simply reproduced as required as a bolt in modification, as will the series Minx or Rapier version. This will allow an easily obtained brake booster to be installed with the option of also going to dual circuit brakes.
Now to get on with panel work and paint preparation.
19th August 2022
Finished?
No there is always room for improvement.
No there is always room for improvement.
There is a fine line when knowing that it is good enough.
Taking a break from panel beating work I had another look at the pedal push rod which did not work out exactly as planned.
Taking a break from panel beating work I had another look at the pedal push rod which did not work out exactly as planned.
The clever little turned piece that I had popped the original master cylinder rubber over did not allow the parts to removed easily if required. The yokes on each end were too large to fit through the hole making removing either side difficult.
I had purchased a Holden bellows to go around the push rod so thought I will rework the piece to use that and make service easier.
I had purchased a Holden bellows to go around the push rod so thought I will rework the piece to use that and make service easier.
It fits in the pedal assembly on the inside, the slight protrusion required the hole through the firewall to be enlarged a few mm. The thickness of the rubber will fit in the thickness of the car body and the 3mm steel used for the booster mounting bracket.
This will allow the pedals part to be removed, and provide a better seal to keep engine fumes out of the interior space.
All was complete, but I decided to install the whole thing in the car to be sure to be sure that it all fitted properly. It is less aggravation at this stage before the body is all prettied up and painted. Before doing this I also removed the now redundant Humber accelerator pedal and linkage because the Mitsubishi will use a cable and the Humber parts come out on the other side. It all came out fairly easy, note to self get a rubber grommet to fill the hole.
Bolted in the pedal assembly, refitted the original rubber seal that goes around the steering column, and mounted the clutch master cylinder as well.
Will leave it in there until I am ready to do the body prep for painting so parts don't get lost.
Bolted in the pedal assembly, refitted the original rubber seal that goes around the steering column, and mounted the clutch master cylinder as well.
Will leave it in there until I am ready to do the body prep for painting so parts don't get lost.
Recruited a little person to take some pictures with bonnet closed to double check clearances.
Snug as a bug in a rug :-)
So we now have engine installed, radiator in place, oil filter sorted, gearbox mounted, driveshaft connected and brakes ready. Almost at the point of rubbing down the body and adding the paint.
No comments:
Post a Comment