Pat's MK4 Build Thread Spencerport, NY - Rear Brakes

[jengum]

My bad. I was using an old FFR instruction for the IRS 11.65 brakes. I see that the latest FFR instruction (Rev C at top of document) now shows the clip installation for the IRS 11.65 brakes. For some reason the lower right title block still shows Rev A.

[PMD24]

Making the switch to an in-tank fuel pump. Blueprint says 255lph and 60psi. That leads me to the Walbro GCA3366-2 on the ProM hangar. Any comments on this decision and selection would be appreciated.

Pat

[gbranham]

That's what I did, and many do.

[M22_COBRA]

Pro M hanger is a nice piece, but you usually have to trim the tank opening to get it in per the instructions. If I did it all over I would use Oetiker clamps on the main body vs the supplied worm drive, may have lessened the size of the hole I had to trim. Also make sure you get the electrical wring harness for your pump, and fuel rated solder seal wire connectors or shrink wrap. Happy Building!

[PMD24]

Thanks M22 - will check out everything you mention before going any further.

[PMD24]

Picking up where I left off on post 80, rear brakes are complete. Found some shims at ACE hardware and finished mounting the PS rear caliper.

Installed the emergency brake cables on both sides. For newbies like me, be aware that it's a challenge. The lower star head bolt for mounting the caliper is directly in front of the hole where the cable end is fastened to the caliper.

Rear caliper bolt LR.jpg

First attempt was to insert the cable into the hold with the screw backed out. While that worked for getting the cable past the smaller diameter screw threads, I wasn't able to tighten the screw because the flange on the head wouldn't clear the metal sleeve on the end of brake cable. Next attempt was to fully tighten and torque the screw and insert the cable after. This is likely the only way to get it assembled AND it requires the hole being opened up as described in the manual. I did not have the issue shown in the manual where the cable end does not fully seat in the hole. Once the flange on the cable end is worked over the head of the screw, the flange does contact the caliper casting and seats fully.

Caliper screw tight LR.jpg

Emergency Brake Cable installed LR.jpg

One thing I want to reshare is using reamers to enlarge or oblong holes. There are lots of testimonials in this forum on the drill binding and wrist twisting from trying to use a drill bit for doing this. I picked up the 1/2" and 5/8" reamers shown below from Amazon. They are relatively inexpensive and worked perfectly on the spindles, center section, and calipers. No binding, no twisting, and no sprained wrists.

Reamers LR.jpg


Next up... routing the emergency brake cable. Instructions don't work.

[PMD24]

The manual and supplemental instructions indicate the brake cable should be routed around the rear of the shock. The first photo below shows that making the bend around the back side (left side in this photo) of the shock without kinking the cable, is pretty unlikely. Since the cable angles down out of the caliper I elected to continue the routing in that direction and run it on the front side of the shock. To keep the cable from contacting the CV joint it has to be fastened to the spindle or control arm. I couldn't access a good mounting point on the spindle so the cable was fastened to the front ear of the control arm

Cable 1 LR.jpg

Cable fastened to control arm ear. Camera angle appears to show possible interference between the nut and spindle, but there is clearance.
Cable2 LR.jpg

Better angle showing nut clearance at spindle and cable clearance at CV joint. This positioning works through the full range of motion for the suspension.
Cable3 LR.jpg

[PMD24]

Making the switch to an in-tank fuel pump. Blueprint says 255lph and 60psi. That leads me to the Walbro GCA3366-2 on the ProM hangar. Any comments on this decision and selection would be appreciated.

Pat

Got the hanger and fuel pump out today and it's a definite no-go. The pump inlet is off center and the sock has a 45 degree connection, so neither works with the hanger. I spoke with Summit before placing this order and they said this was the right choice. I asked about the GCA719-2 that I read about here in the forum but they couldn't find any info on the pressure. They also seemed to indicate it's no longer available. So, I placed the order.

My research now points to the GSS340. The Walbro website doesn't provide pump curve data to establish what the flow is at 60 psi, but it does state 210lph and 80psi so it's highly likely it will flow at 255 at 60. Will speak with Walbro on Monday to verify, and then pursue the return with Summit.

[PMD24]

Spoke with Walbro directly. A real live person picked up the phone on the second ring. Knowledgeable and great service. GCA719-2 and GSS340 are both still available. GCA719-2 is a kit that includes the GSS340 pump along with the sock, electrical whip, hanger hose, clamps, and some misc hardware. GSS340 is a stand-alone pump. GSS340 will develop the required 60psi at 255lph. Details on performance, including pump curves, for various TI products can be found at aftermarket.tiautomotive.com. TI owns Walbro and has made their pumps for many years. The number to reach Walbro direct is 989-672-8383.

[PMD24]

Drained center section and added 3.3 pt of Motorcraft 75W-85 synthetic hypoid gear lube with 3.5oz of Motorcraft friction modifier. This filled the case to just below the fill hole. Installed vent. Shortened the vent tube a bit and fastened it to frame. Used a Dorman 924-284 (Amazon) differential vent on the end of the tube.

Center section vent LR.jpg

[gbranham]

I'm curious why you drained a new diff, only to fill it back up. They ship from Ford full, or nearly full. I only had to add a smidge to it, and it also already has friction modifier in it.

[PMD24]

I'm curious why you drained a new diff, only to fill it back up. They ship from Ford full, or nearly full. I only had to add a smidge to it, and it also already has friction modifier in it.

I was able to detect oil through the fill hole only by sticking a piece of wire in and down, so I wasn't sure how much was in there. Decided to drain it to measure amount. Upon draining I noticed a few small metal shavings, so I elected to replace it. I also couldn't detect any odor of friction modifier... but I also have a bad sniffer so can't be sure about that.

[PMD24]

Catching up here on some things that were completed recently. PS footbox, floor and under-door sheet metal wrapped up. Panels went together well.

Power steering rack installed with no issues. I had ordered the Breeze centering bushings and then found that there was some debate here on the need for them on the MK4. Installed them and did use them to shift the rack approx 3/8". Don't know if that amount matters, but it's now centered. The slot in each of the bushings, which are normally at 6 o'clock are now at 5. Also, I was able to get the 53 1/16" dimension specified in the manual, using the FFR provided tie rod ends, and no trimming of the tie rods.

In photo, rotors appearing to point outward is due to setting camera on wide angle.
Power Steering rack LR.jpg

Pedal box installed. No issues other than the clutch pedal/frame interference thing that seems to be very common. Read a few times here that this interference issue was resolved on more recent MK4's, while others indicated it wasn't. In my case the pedal contacted the frame with approx. 1.5" of travel left to the front wall. Of the two options discussed here in the forum I chose grinding of the pedal arm web over altering the frame. Both options alter the existing structural integrity so neither gives me a warm fuzzy. My logic in choosing the grinding was that the hydraulic clutch likely puts my pedal force well below what the arm is capable of for handling manual forces on builds with much heavier clutch pedal requirements. But, I'll be sending the photo below to FFR tech support for a nod and will report back on their response.

EDIT - UPDATE 2/3/25 - spoke with FFR tech. As expected they couldn't give an absolute yes or no on the material removed from the pedal casting, but didn't express concern. The important thing that they shared was that the pedal striking the frame should not be a problem. Full travel needed should occur before hitting that stopping point. They were more concerned with over-travel and impact on the clutch master cylinder. They suggested that once I have the drive train in, hydraulics operating, and work through adjusting the clutch, that I add a stop to prevent excessive pedal travel. When I get to that point, I will post a new entry that refers back to this post, to ensure the end result is shared.
Clutch pedal LR.jpg

Steering shafts and bearings installed with no issues. The upper u-joint is a little close to the footbox bearing retainer. It doesn't rub, but I will shift the whole assembly down by 1/8" or so. I have room where the lower u-joint connects to the rack. Spring washers went into shaft and tube without issue and there is no lateral play that might have required the set screws described in the forum.
Photo below shows how close the upper u-joint is to the bearing retainer. Easy fix.
Steering ujoint LR.jpg

[PMD24]

Just a quick item for those doing the pedal box for the first time. The manual shows a photo of the switch brackets being held in place for marking the point to drill the mounting hole in the pedal box casting. Note that when you mount the bracket do NOT mount it there. The second photo shows the bracket mounted on the front side of the drilled casting web. It's important to place it there because the switches may not reach the pedal arms if the bracket is mounted on the rear side of that web. In the photo below you can see that if the bracket was 1/4" further back the switch would not contact the pedal arm. I do have some concern that the switches won't reach the arms when pedal adjustment is done, but will address that if/when it happens.
Pedal switch LR.jpg

[PMD24]

After years of trying different things to prevent caulk from drying/curing in the tube I finally found something that works. Got it at Lowes. Don't have the packaging but I found it in the paint section near the brushes and rollers. No more tossing partial tubes of silicone as you work through the sheet metal stages.

caulk saver LR.jpg

[gbranham]

I always just shove a drywall screw in the silicon tube. Keeps it from drying out for months