What MC for LS1 front/rear discs on Chevelle?

[kst8engineer]

I just completed the swap of LS1 front and rear discs onto my '71 Chevelle. I also swapped the clutch/brake/gas pedal assembly and power brake booster from the '99 T/A donor car onto the Chevelle. The car currently has a Chevelle disc/drum master cylinder, and I'm debating what to replace it with.

I have two 4th-gen F-body master cylinders (one from a '94 disc/drum car, and one from a '99 4-wheel disc car) that I've considered using. The problem with these is the steep angle of the reservoir to the master cylinder body (see pic below). Since the Chevelle firewall is nearly vertical, this puts the MC reservoir at a significant backward tilt. I believe the '99 T/A MC is a 1" bore, and since I've got the rest of the braking system from this vehicle, I'm thinking that's probably the bore size I should go with.

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Does anyone have suggestions for what MC alternatives I should consider? I'd rather stay away from the older iron designs (personal preference).

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I really like the Wilwood 260-8555 master cylinder (above), but I'm having trouble letting go of $200 for it. For reference, I'll be using a Wilwood 260-11179 proportioning valve.

https://static1.pt-content.com/images/pt/2010/08/95026011179-1.jpg

Suggestions would be appreciated. On the other hand, if anybody has experience running the F-body master cylinder with the reservoir at this type of an angle, I'd be interested to hear that as well.

[kst8engineer]

Derekf mentioned that the booster may place some of the angle on the master cylinder, and he's right. Even with this, though, I believe the reservoir will still be at somewhat of an upward angle. I may be able to do some measuring tonight to get a better idea of what the angle would be.

https://static1.pt-content.com/images/pt/2010/08/547128701-1.jpg

[bullitt4110]

I havent installed it yet but I went with the Dodge 24mm master, it is aluminum with a plastic res. I am also doing manual brakes though (my car is factory manual brakes). This master was suggested by Tobin@Kore3 for use with LS1 brakes on all four corners.

[kst8engineer]

I did a little looking at the 4th-gen F-body power brake booster, and it appears that the bracket on the back of the booster angles the booster and master cylinder upward approximately 13-15 degrees.

I need to maintain the mounting bolt pattern of the F-body booster (my clutch/brake/gas pedal assembly mounts to it), but maybe I should consider a booster from a different application that doesn't put this significant angle on the booster and MC. Alternatively, maybe I could cut and reweld the booster mounting bracket to improve the angle.

[jski67]

I played with this a little while ago on my 67 camaro...

You can easily remove the mounting brackets from the 4th gen booster. Tuff Stuff makes generic GM booster brackets for their boosters...I mocked up a set of their brackets on the LS1 booster and it would have worked fine. If I remember correctly, the Tuff Stuff brackets lowered the angle of the booster compared to the stock LS1 booster bracket.

Unfortunately for me, the stock booster hit my BBC valve covers, so I went with a dual 8 inch unit.

If you don't like the slant of the LS1 master reservoir, you can run one from a C5 vette, which is more level. The two m/c's are the same, except the port location and resevoir shape.

I have LS1 brakes and I ended up using the C5 master (to get the ports facing away from the engine) with a ls1 reservoir (to fit under the hood).

I've still got the c5 reservoir if you need it...

Jason


Pic of C5 reservoir on LS1 m/c...
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[srh3trinity]

That tip on the Tuff Stuff brackets sounds like a nice solution. There is a guy with a second gen F-body that cut off the brackets on his original master and welded them to an LS1 Fbody master.

[jski67]

Here's a pic of the TuffStuff brackets on the stock LS1 booster. You just have to grind down the big rivets on the booster and the old bracket will pop right off.

After I thought about it more, I'm 99.9% sure I got the brackets through Summit...they were listed as Summit brand brackets but said TuffStuff when I opened the package.

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