Wilwood power brakes

[NICK C]

I have the Wilwood brake system that comes with the complete kit. I am now at the point of fitting the brake pedal assembly. I am looking at the power brake kit that Whitby offers. Has any one used that kit and how far can I go into installing the pedal assembly without having to remove it before putting in that power kit. I have e-mailed Whitby but probably won't get a response till after the weekend. Since that kit has a single master cylinder placed on the opposite side of the foot box, with the booster, rather than the two MC's I fear there may be some turn of events that may surprise me. Any comments are appreciated.

[Scott Zackowski]

Nick C,

I used the Whitby Power Brake set up on my Mk4 Complete Kit. I recommend it! For more details you might do better to call Whitby. It does require modifications to the frame (to allow the Booster to fit), front foot box plate (steel) and aluminum cover plate. You will also have to modify the pedal box bracket. If you have the pedal box bracket pictured in the manual, you will have several holes to cut into the bracket and trim the lower edge to allow the steering bracket to fit on the the inside of the plate. If you decide to go with their kit, do not permanently attach the aluminum cover plate. It is okay to assemble everything else as a mock up to see how things go together but you will end up taking everything part (several times) while making the modifications to get the Power Booster to fit.

The extra grinding and drilling is well worth it though in the end. It is a well designed kit but not a "true direct fit".
If interested, I can sen you some pictures of the modifications required.

SWZ

[NICK C]

Thanks Scott. Do you have any pics?

[Scott Zackowski]

Nick C,

I will get the pictures together and post them.

SWZ

[NICK C]

Thanks.

[Scott Zackowski]

Nick C,

They depict:
1) PowerBrake Kit (you will also get a new brake pedal)
2) Layout of the driver foot box front steel plate. Need to enlarge the center hole to accommodate the booster lever that attaches to the brake pedal. The holes for the booster bolts to go through.
3) Modifications to the pedal box frame. One the blue painted (final mod) the rounded notch at the bottom to allow for the lower steering bearing to be moved to the inside of the foot box steel plate. This is required for clearance of the power booster - otherwise the booster hits the steering bearing.
4) Modifications to the foot box aluminum panel.
5) Solid frame bracket to allow power booster to fit.

Sorry about the pics being out of sequence.


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SWZ

[NICK C]

Scott I appreciate your time. The pics give me a better idea of whats going on. I sent an e-mail to Whitby last week, but haven't had a response yet. I'll call at my next oppurtunity. You say you got the complete kit. Did you have any issues with the fuel pick up being too long and hitting the bottom of the tank? When I have the pick up positioned at the right orientation, I've got about 3/4 inch space to make up if I plan to close it down on the flange. It looks like there may be enough room to be had if I could slide the filter screen up the tube some, but it seems to be bonded on. Any comments? Thanks.

[Bob Cowan]

When I bought my Wilwood brakes from Gordon Levy, he recommended not using a booster. He said that made them too sensative, and difficult to modulate. I'm using 6 pistons in the front, and 4 pistons in the rear.

[tjmotter]

I installed the Whitby kit with the Wilwood pedals as well and am very happy. A couple of observations:

1) The initial spacing on the brake pedal pivot was too high. It came setup for a 7:1 pedal ratio which is optimal for a manual braking setup but I found it too soft so I ground out the stud and moved it down to a 4.9:1 ratio and love it. I have GREAT feel but also have incredible stopping power.

2) You have to be very careful (measure 3x and cut once) when you are working to fit the booster. The 4 mounting holes lined up pretty well (some minor cutting to get a good fit) but the center hole is critical. The way I chose to do this was to remove the metal adapter for the pedal box (picture #1 in Scott's post) and use a hole saw to drill through the front of the footbox. Next, I checked the fit to ensure that the booster would fit. Once that was confirmed, I reinstalled the metal adapter and drilled through it as well. You should also note that the two holes shown in the pic above (right on the bend in the metal) don't exist so you have to cut these out with a grinder so that you can get the bolts onto the booster.

I wrote lengthy post on this on the other forum ("Whitby's Power Brake kit - Modding the mod") that you may want to take a look at. In the post, Whitby's responded that they were planning to make some changes to the brake pivot to improve the design.

HTH
Todd

HTH
Todd

[Scott Zackowski]

Todd,

I got my Whitby kit this August - it came with a steel brake pedal - to replace the Wilwood pedal. Did your set up come like this? I am not at the point yet to know how the brakes feel. Do you think the replacement pedal is the correction Whitby was talking about?


Also Nick,

Todd has good points about making the cuts precise. I made all the cuts in the front foot box metal plate first. Your plate already has a round center hole - it just isn't big enough or high enough. Whitby just grinds the center hole to the appropriate size, and I did the same thing. It is tedious (metal reamer/grinder works best) but allows to slowly get the hole to the right shape. So you grind some and then try to fit the booster. Eventually you can get part of the booster rubber boot in and then trace or mark the opening size needed. Also note that the rubber boot comes off allowing you to get the booster part of the way in - allowing you to fit the bolts into their respective mounting holes. Three of the bolt holes will line up with existing holes in the foot box plate. The 4th one (lower engine side) will have to be marked and drilled. The center hole has to be made big enough that the rubber boot does not touch the sides of the plate at all. If it touches it may bind and cut the boot. Once you have the booster fitting and mounting properly into the foot box metal plate it is time to mock up and make you cuts into the pedal box frame. The center hole for the pedal box frame will not have to be as big as the hole in the front foot box metal plate. The metal plate hole will come out oval (see picture #4). The hole in the pedal box frame can be round (2 1/2 inches). The holes in the pedal box frame for the booster bolts were made by using a hole saw to cut 2 round holes on the top of the frame and then used the Dremel Tool with cut off blade to "rough" cut the notches on the front of the pedal box frame. I then smoothed and round it all out the pneumatic angle die grinder. The holes have to be big enough for you to get a wrench around the nuts, and I made the front edge of the holes deep or low enough so that the nut cleared the pedal box frame and secured up against the front foot box plate.

Also, also Nick,

Regarding your question about the gas tank. You are ahead of me on that portion to the build - so I have yet to encounter that problem. You might want to pose the question to the FFR tech guys. I am currently installing the FF heater unit. I have delayed installing the gas tank because I have yet to decide on whether I am going to sink the battery box.


SWZ

[tjmotter]

Scott,

Yes, I received the same pedal. LOVE the AC pedals.

I suspect the pivot is ok but there are two ways to confirm. One is to measure the length and calculate the ratio. The other is to check closely on how the pedal connects to the pushrod. On mine, the pushrod was pressed quite hard onto the top of the booster and would rub. After I moved the pivot it was centered.

Hth
Todd


Todd,

I got my Whitby kit this August - it came with a steel brake pedal - to replace the Wilwood pedal. Did your set up come like this? I am not at the point yet to know how the brakes feel. Do you think the replacement pedal is the correction Whitby was talking about?

SWZ

[NICK C]

Todd, Scott thanks for the info. I talked to Jeff at Whitby's today and ordered the kit. I'll save your info here and use it wisely. Scott I figured out the fuel pick up problem. The tube was 3/8 to 1/2 inch too long. I simply, carefully, broke loose the filter screen, which seems to be bonded to the tube, and slid it off the tube. Then I cut about 3/8 inch off, smoothed and replaced on tube. It is still a tight fit. I put it in the tank and it fit well. Mine was long but I don't know if they are all like that or just part of a bad batch. When you get to that point, this may help.

[NICK C]

I finally got the front plate drilled and modded and the booster is in. I was having issues with the booster hitting the steering shaft bearing, but with the wisdom of Yoda, a quick text to Jeff at Whitby's, a simple moving of the bearing to the other side of the footbox wall solved the problem. Also, if I had looked more closley to the instructions, I might have figured it out. Todd or Scott, how did you mount the AC pedal to the wilwood clutch radius? I am a little baffled on how to do it and have it look good?