Need more travel on the brake booster - how best to adjust? (1 Viewer)

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Hope everybody had a good weekend.

So I have the new brake system installed on the 1968 FJ 40 that has the SBC in it. I used a mini truck/Lexus combination for the brake booster and master cylinder, everything fits up nicely but I am about a half inch shy of the brake travel that I need.

In other words the brake pedal is being held too close to the firewall by the clevis pin. I either need a longer clevis pin OR do I need to adjust the booster to the master cylinder.

Any been there/adjust that suggestions?

Thanks!

 

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I pulled the master off the booster, and it looks like I have some adjustment here, but I think it is pedal to booster where I need some additional length.

 

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OK-there comes a time to talk to a pro so I went to a brake specialist and they indicated that the mini truck pushrod boosters are they fixed wing meaning that I need to adjust the length of the clevis pin for my travel issue .

 

[1911]

Aren't there threads that the pedal clevis screws on to? There are on Toyota vacuum boosters.

You need to adjust the master cylinder pushrod (the one in your photo) so that there is the tiniest bit of clearance between it and the master cylinder piston when the pedal is not being pushed. The factory service manual specifies a range of 0.1 to 0.5 mm (0.004 - 0.02"). If you tighten it beyond that, you will bugger the valving functions of the master cylinder and probably wear it out prematurely, so don't use that to adjust your pedal.

 

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@1911 - thanks for the response.

The push rod on the booster does have threads but I’m still short travel with the clevis all the way backed off the near the end of the threads.

Good tip on the front adjustment. How do you measure that gap?

 

[ferg]

OK, when I installed mini parts on my '66 I had the same problem. At issue is the fact that your '68 was not designed for a booster and the pedal travel reflects that. My fix after struggling to figure it out was to measure a factory disc setup on another 40. I found that the later disc/booster set up was higher off the firewall floor(more pedal travel) than the '66. It needs to be raised about an inch and a half.

I cut and bent/raised my pedal arm to get the correct amount of room for proper brake operation. How you choose to fix it is of course up to you. Would a later pedal assy fit? I don't know as I didn't look into that.

 

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Thanks @ferg , appreciate the confirmation that I'm not losing my mind.

Not visualizing how you raised your pedal arm unless you cut the factory brackets?

Thanks!

 

[ferg]

Cut the pedal arm. The one that hangs down and you push on it with your foot. I'll bet yours goes almost to touching, or actually touching the floor.

 

[1911]

Good tip on the front adjustment. How do you measure that gap?

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Cut the pedal arm. The one that hangs down and you push on it with your foot. I'll bet yours goes almost to touching, or actually touching the floor.

Good morning @ferg I think our set up is different. I used a mount from JT Outfitters to mount it in the stock location and I have a GM steering column so I have to make sever beds in the pedal.

I can see where if I had a stock column and straight pedal it would hang down.

@1911 / thanks, will check it out.