| If affordable and easy to install, would you prefer power assist brakes on your T4? |
| Heck Yea! |
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90% |
[ 9 ] |
| No Way |
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10% |
[ 1 ] |
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| Total Votes : 10 |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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 Posted: Thu Aug 18, 2016 4:18 pm Post subject: Re: Power Assist Brakes |
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| titan3c wrote: |
OK----I just went out and checked it out. After looking at my car, and comparing it with the pictures Lars-s has sent of the power assist system I come to this conclusion. The push rod on the power assist comes thru the fire wall in line with the center of the bracket. The push rod on the non assist of course is to the right of the bracket, but appears to be on the same level as power assist. The modification Ray is working on is feasible, but will just have to locate to accommodate the push rod location. Another thing that puzzles me is the punch out I'm thinking of is at an angle---I must not be looking at the correct punch-out but don't see another one.
Also - if making this change one chooses to use the std servo bracket under the hood he would have to change the pivot shaft on the pedal cluster also. Bob |
OK...a few items.....
First....Lars...thank you for that picture! I knew it was routed that way from the parts charts...just had never seen a picture of one.
titan3c:
Yes...there is plenty of room above the pedal cluster. I just went out and looked. The curved part you are feeling is at the very foreward end of the pedal cluster where it attaches to the firewall.
Where I am speaking of putting the A-frames is rearward of that. There is approximately 2.5" minimum and 3" maximum of head space above the pedal cluster. The first thing you will hit the is the wiper motor.
The stock power brake set up has a very different brake pedal cross shaft. On the non-power brake unit...the shaft is stationary and the pedals revolve around the shaft on bushings.
On the power brake unit pedal cross shaft.... is physically attached to the brake pedal...either welded or splined or pinned...I don't know which.
The lever that moves the FIRST pushrod on the power brake set up is both keyed and splined to the pedal cross shaft. That is the push rod that goes upward through the rectangular hole in the pedal cluster and through the fire wall hole at an odd vertical angle.
There it intersects the relay lever in the trunk which is kidney or cam shaped and sits on a short cross shaft in the bracket aft of the booster you can see in Lars pictures about four posts back.
Here are the parts diagrams:
The manual brakes are at the top of the page and the power brake version is at the bottom.
AA detail shot...the parts circled are the tab that mounts the pushrod to the pedal cross shaft , the key and the pin
The parts list
Here is the brake booster unit. You can see the bracket for the relay lever which is inside of the trunk...not under the dash.
A details showing the kidney shaped relay lever and the short cross shaft it rides on.
The parts list
Here is looking under my dash. Sorry for the mess. I have not done anything under here yet in a long time so lots of stuff hanging out.
This is actually a type 3 master cylinder ...I think...have to check my book to see what I left in here. It may be a superbeetle master cylinder with type 4 springs. can't be sure.
In this shot...if you look carefully you can see the wiper motor above. There is a bare minimum of 2.5" head room above the pedal cluster top.
This is the modification I did back in 2001. I welded a bracket to the cluster to take a normal master cylinder. I have to grind the inner ear down on the master cylinder in order to fit...and its a real paint to install.....but it works.
It is not ideal because it STILL is under the dash and makes a rusting mess getting it installed or removed.
Because of the solid shaft attached to the pedal on the power brake unit...is why I decided it would simply be easier to use the existing crank end at the top of the existing pedal to run the pushrod ABOVE the pedal cluster.
Looking under the dash.....in this sketch.....looking from the passenger side toward the drivers side....this is more like what the "A Frame" bracket may have to look like.
The two green bolts are where the plate bolts on to where the original master cylinder was. A window has to be cut in the A-frame plate to allow the existing pedal pushrod to connect to either the pivot disc or bar that is suspended from the cross shaft.
Yes...I have seen the strange geometry of the hole in the firewall. The master cylinder in the trunk may need to be at a slight angle. Ray |
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ClassicCamper
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Joined: December 17, 2002
Posts: 679
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| Posted: Thu Aug 18, 2016 9:49 pm Post subject: Re: Power Assist Brakes |
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So... Here is the part a great VW friend has to offer. Only issue is that the cluster is for a manual transmission, not an auto like mine.
Can I attach my existing auto trans (single pedal) cluster to the servo/master cylinder assembly? Here it is:
Looking forward to feedback.
_________________
1973 412 Wagon
1976 Westy
1978 SB Vert |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Thu Aug 18, 2016 10:25 pm Post subject: Re: Power Assist Brakes |
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Interestingly enough the parta book does not show a complete explicit diagran for a manual trans pedal assembly with power brakes.
But....it should be no real problem depending upon how the clutch pedal is set up. From the parts books.....it should be a solid shaft attached to the brake pedal ....with the relay lever keyed and pinned to it....and the clutch pedal should have its own bushing and just ride on the end of that shaft. So.....you should be able to remove the snap ring and spring and clutch pedal and all should work.
But...I am bettjng that since the snap ring and pedal bushing probably keep the brake pedal and shaft from walking out to the right.....you will need a bushing or a stack of washers where the clutch pedal and bushing were and the snap,ring to keep the shaft in place.
Ray |
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titan3c
Samba Member
Joined: February 16, 2012
Posts: 568
Location: Coweta, Oklahoma
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| Posted: Fri Aug 19, 2016 4:01 am Post subject: Re: Power Assist Brakes |
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OK, I get it all, btw I would love to have one of the power steering pedal clusters classic camper shows. I would install it, but not use the servo. I would use Ray's plan for a mc under the hood.
One comment Ray. On your drawing you show the disc to the right of the cluster which would put the push rod going thru the fire wall to the right of the pedal cluster. If the cross shaft on your drawing had a arm in the middle of the shaft for the push rod, then it would be in the same line as the power steering push rod. Does that make sense? Bob |
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titan3c
Samba Member
Joined: February 16, 2012
Posts: 568
Location: Coweta, Oklahoma
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| Posted: Fri Aug 19, 2016 4:27 am Post subject: Re: Power Assist Brakes |
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| I just now think I understand your last drawing about the window. I think you are moving the disc in the middle of the cluster. Bob |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Fri Aug 19, 2016 9:55 am Post subject: Re: Power Assist Brakes |
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| titan3c wrote: |
| I just now think I understand your last drawing about the window. I think you are moving the disc in the middle of the cluster. Bob |
Yes...you beat me to the explanation  !
That first sketch was made before I could make absolutely sure that there was room under the wiper motor on top of the pedal cluster.
And...I know you "can" put the pivot disc on the outboard side....but yu would have to to do this....here are a pair of top view sketches
If for some reason the pivot bar/disc/lever....needs to be larger than the space above the center of the pedal cluster can provide...and you need to put it outboard of the A-frame plate....you will need to "crank " the pushrods (green)
However....I also have the added issue...that I would like to get the clutch master cylinder out from under the dash as well....
So based on my sketch from yesterday I would have a pair of windows cut in the A-frame plates so that the pushrods from clutch and brake pedals...which are outboard.....can access the pivot discs/bars in the center between teh A-frames and over the pedal cluster centerline.
So...if I can get it all in the center over the pedal cluster between the A-frames....I would have two 13mm diameter pushrods
And to get the clutch master and brake master on the same plate in the trunk with correct geometry...without a second relay pivot in the trunk (may nt be possible...have to check the angles)...I am suspecting that both cylinders will need a slight angle and it would pay to put the smaller clutch master up slightly higher and steeper angle for brake line access. Ray |
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titan3c
Samba Member
Joined: February 16, 2012
Posts: 568
Location: Coweta, Oklahoma
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| Posted: Sat Aug 20, 2016 6:13 am Post subject: Re: Power Assist Brakes |
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I'm liking what your doing. Fortunate for me I just have to be concerned with the brake system since I have a automatic trans.
Next week I will be removing my pedal cluster, and I plan to make a simple wood mock up of this and install it on the cluster while it's on the bench. Let me know if you have any specific dimensions figured out yet.
My plan is then to fabricate and acquire parts, and install on the cluster before reinstalling it.
Just an after thought-----if feasible to do so----I could ship my cluster to you to work with. As I said just a thought. Bob |
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titan3c
Samba Member
Joined: February 16, 2012
Posts: 568
Location: Coweta, Oklahoma
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| Posted: Sun Aug 21, 2016 6:31 am Post subject: Re: Power Assist Brakes |
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| Another comment on clissicamper's question about using his existing cluster instead of the power assist cluster. There is a difference in the two clusters. Notice that the power assist cluster has a vertical side bracket on each side on the firewall end which matches the bracket on the other side of the firewall. I guess the purpose of this is to "beef-up" the strength of the firewall attachment area, and put the pressure on the cluster instead of possibly warping the fire wall. Bob |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Sun Aug 21, 2016 8:21 am Post subject: Re: Power Assist Brakes |
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| titan3c wrote: |
| Another comment on clissicamper's question about using his existing cluster instead of the power assist cluster. There is a difference in the two clusters. Notice that the power assist cluster has a vertical side bracket on each side on the firewall end which matches the bracket on the other side of the firewall. I guess the purpose of this is to "beef-up" the strength of the firewall attachment area, and put the pressure on the cluster instead of possibly warping the fire wall. Bob |
That vertical bracket you are speaking of....I am pretty sure is a seperate part. It bolts on or rivets on....to the pedal cluster.
I will dig in the parts book and see what we can find. Ray |
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titan3c
Samba Member
Joined: February 16, 2012
Posts: 568
Location: Coweta, Oklahoma
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| Posted: Mon Aug 22, 2016 6:02 am Post subject: Re: Power Assist Brakes |
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| I might me getting a little ahead of the details, but I'm struggling with how to secure both ends of the cranked push rod. It will naturally have a gravity pull down at the cranked position. So how do you solidly connect the ends of the cranked push rod to the disc so it doesn't have a tendency to droop? I'm sure your more versed than me on how this is done. Bob |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Mon Aug 22, 2016 7:45 am Post subject: Re: Power Assist Brakes |
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| titan3c wrote: |
| I might me getting a little ahead of the details, but I'm struggling with how to secure both ends of the cranked push rod. It will naturally have a gravity pull down at the cranked position. So how do you solidly connect the ends of the cranked push rod to the disc so it doesn't have a tendency to droop? I'm sure your more versed than me on how this is done. Bob |
I'm not exactly sure what you are asking. The ends of the pushrod are secured to the disc (or pivot bar).....by one of two ways.
1. Using hardened shoulder bolts going through holes with bronze bushings in the holes in the ends of the rod.....with both faces of the rod where it connects to the shoulder bolt.....ground flat. The shoulder bolt threaded part goes through the pivot ppqte and has a nut and lockwasher for safety.
2. Same as above. ...but using a stud protruding from the pivot bar instead of a shoulder bolt...and a nut on the outside with a pair of thrust washers and a cotter pin for safety.
You can also use rods with forked ends like stock but there is no real advantage.
I have also been redesigning this a bit and will get a sketch out later. Instead of the A-frame plates being on the outside surface......if you only have an automatic and no clutch......you could take a simple piece of sturdy angle iron.....like 3/8" thickness and 3" X 3" legs.
A short section.....maybe 3"-4" long can be mounted just offset of the centerline of the pedal cluster on top. You may have to grind it just a little on both legs for clrarance under the wiper motor.
Bolt it to the cluster with two 10-12mm bolts. Its now just offset to the left of the centerline of the master cylinder hole to the trunk. Install a shoulder bolt or stud and mount the pivot plate.
In this configuration......ins stimpler now to install a longer clevis pin at the top of the pedal. Make it slightly larger in diameter.....about 12-13mm diameter.
Now the pushrod from te pivot plate to the MC is straight instead of cranked. And now the clevis lin from the top of the pedal reaches straight across to the left enough to be inline with the pivot plate. And....the pushrod between the clevis pin and tje brake pedal is now straight. Ray |
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titan3c
Samba Member
Joined: February 16, 2012
Posts: 568
Location: Coweta, Oklahoma
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| Posted: Tue Aug 23, 2016 5:35 am Post subject: Re: Power Assist Brakes |
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| I like this idea. I'll look forward to your drawing. I'm having trouble picturing the connection from the top of the pedal to the pivot disc. It sounds like that is connected straight from the top of the pedal to the pivot disc. That being the case then the pivot pattern of the disc and top of the pedal wouldn't match, and that would be a problem. I'm sure I must have this wrong-----I'll wait for your drawing. Bob |
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raygreenwood
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Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Tue Aug 23, 2016 5:46 am Post subject: Re: Power Assist Brakes |
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| titan3c wrote: |
| I like this idea. I'll look forward to your drawing. I'm having trouble picturing the connection from the top of the pedal to the pivot disc. It sounds like that is connected straight from the top of the pedal to the pivot disc. That being the case then the pivot pattern of the disc and top of the pedal wouldn't match, and that would be a problem. I'm sure I must have this wrong-----I'll wait for your drawing. Bob |
Understand.....that the angle of the input pushrod to the pivit disc (from the top of the pedal)....and the output angle of the pushrod from the pivot disc (to the MC) will be different.
Making them 1:1 is accomplished by varying how far from the center/vertex of the pivot disc each pushrod is mounted.....and where in degrees of arc the pushrod is attached to the disc. Ray |
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ClassicCamper
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Joined: December 17, 2002
Posts: 679
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| Posted: Sun Aug 28, 2016 9:25 pm Post subject: Re: Power Assist Brakes |
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Here is the pedal configuration I have to work with if I sping for this power assist set-up. I need to comb through all of the posts recently added. I was wondering if I could remove my large brake pedal arm/foot pedal and use it on the power assist mechanism less the clutch pedal arm.
All of the alignment is going to be interesting. I wonder if I'm getting in too deep with this lol. However, everything I've done with this car has been a product of fabrication.
Still debating if I want to buy this. As they so though, nothing ventured...
_________________
1973 412 Wagon
1976 Westy
1978 SB Vert |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Sun Aug 28, 2016 10:30 pm Post subject: Re: Power Assist Brakes |
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Yes.....you should be able to use your existing brake pedal. Note the unused clevis pin at the top of the brake pedal. That is what connects to the pushrod for the non-power brake version.
Or is that your original pedal on the shaft that we see in the pictues?. The issue is that the non power brake pedal.....turns on the cross shaft.....while the power brake pedal. ...turns the shaft itself. So your existing brake pedal must be pinned or welded to the shaft. Ray |
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Kharon8
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Joined: March 05, 2011
Posts: 375
Location: Espoo, Finland
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| Posted: Sat Sep 03, 2016 3:29 pm Post subject: Re: Power Assist Brakes |
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I've automatic gearbox and power brakes from factory in mine, any picture requests?
The car is on the parking lot so almost zero effort to me and might help.
_________________
Kharon -- '62 typ1, '63 typ14, '61 typ21, '65 typ34, '74 412, '75 typ26
FVWA.fi support group. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Sat Sep 03, 2016 5:37 pm Post subject: Re: Power Assist Brakes |
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| Kharon8 wrote: |
I've automatic gearbox and power brakes from factory in mine, any picture requests?
The car is on the parking lot so almost zero effort to me and might help. |
Some pictures of how the pushrod in the center of the cross shaft that is actuated by the pedal is connected to the shaft. Also the angle of that push rod to the relay pivot between the booster and the trunk firewall mightchelp a few.
Really the easiest way for me to find out what is required to do a mod and move the standard brake cylinder to the trunk is to start mocking it up. Ray |
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Kharon8
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Joined: March 05, 2011
Posts: 375
Location: Espoo, Finland
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| Posted: Wed Sep 07, 2016 9:27 am Post subject: Re: Power Assist Brakes |
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Hello!
I was looking into this and realized that everything under the dash is covered by covers, so I have to remove those first.
But I'll find some time in the weekend if it's not raining too much.
_________________
Kharon -- '62 typ1, '63 typ14, '61 typ21, '65 typ34, '74 412, '75 typ26
FVWA.fi support group. |
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Kharon8
Samba Member
Joined: March 05, 2011
Posts: 375
Location: Espoo, Finland
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| Posted: Sun Oct 30, 2016 5:48 pm Post subject: Re: Power Assist Brakes |
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Augh, I've totally forgotten this.
And now the car is in winter storage, not too easy to take pics.
If this still is current, please someone kick me/send PM.
_________________
Kharon -- '62 typ1, '63 typ14, '61 typ21, '65 typ34, '74 412, '75 typ26
FVWA.fi support group. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21507
Location: Oklahoma City
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| Posted: Sun Oct 30, 2016 8:10 pm Post subject: Re: Power Assist Brakes |
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| Mine is q slow process. I am still busy with the front end. Brakes maybe after Christmas. Ray |
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