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Front caliper clearance and bleed

Posted: Tue Jun 11, 2013 12:00 pm
by jeremiahnz
Hi All,

Finally got my barn up and going and car gear out of storage so I am getting back into my 410 project.

A couple of snags I have just hit which I would like some opinions on

1) Due to where the cross member extends to, there is risk of fouling the brake line where it enters the caliper if you were to hit a bump on full lock. The easiest way to address this is to mount the caliper up the otherway which means the bleed nipple will face downwards. I understand this isn't ideal, but is there any sort of legal/cert issue with it?

2) I had planned to use hubcentric spacers on the front hubs to help clear the calipers, however the hub extends so far at a relatively wide diameter that even using the thickest certifiable spacers (27mm) the ID of the hub centric lip that the wheel will sit on fouls on the OD of the hub. I'd rather avoid modifying the hub as I think it will lead to more issues. So my question becomes, will I be able to get mags that can clear a caliper that sits about 50mm proud of the top hat on the rotor? I have included some pics to demonstrate the issue. You may ask why I used 4 pot calipers - the reason is two pot and single pot calipers I tried protruded too much at the rear of the caliper, fouling on the cross member and/or suspension setup. This is also why I used an evo rotor which has a relatively low top hat. I guess my alternative would be to look at some after market calipers such as wilwoods, which may have a lower width.

Pictures:
rx7caliper1.JPG
rx7caliper2.JPG
Maybe something like this would clear?
Image

Keen for any thoughts/ideas.

Re: Front caliper clearance and bleed

Posted: Tue Jun 11, 2013 12:14 pm
by 85_Z31
I had the same situation with my front brake swap.

I pretty much had to use a 20mm Hub centric spacer AND get the hub machined to suit.

man that hub has a super long spigot on there

Re: Front caliper clearance and bleed

Posted: Tue Jun 11, 2013 2:23 pm
by jeremiahnz
85_Z31 wrote:man that hub has a super long spigot on there
Yep, and long spindle in behind it, hence why I want to avoid machining down the hub, as I'd imagine it could become a longwinded process (hub and then spindle and then possible redrill spindle for split pin etc. etc.). However keen to hear if anybody has taken this approach before and if there were any gotchas?

Re: Front caliper clearance and bleed

Posted: Tue Jun 11, 2013 9:11 pm
by sr1600
Have a look at Chris g1 1600 and you will see you can mount the disc on the backside of a 910 hub gives effectively spacing the calliper at the same time.

Re: Front caliper clearance and bleed

Posted: Tue Jun 11, 2013 9:46 pm
by spiderwebfx
I'll just throw it out there, but keep an eye out for some of the early to mid 90's ROH wheels. They have massive inner clearance on wheels.

This is my S12 on 15x7 +6 ROH's with 4pot front calipers and rotors from an S14. No spacers on it. Yes they are 5 stud, but that's no the point I'm getting at.

Image

Re: Front caliper clearance and bleed

Posted: Wed Jun 12, 2013 10:17 am
by torqued
My Rx7 calipers are almost flush.
If they didnt have the fluid bridge that extends outside the caliper they would be

Re: Front caliper clearance and bleed

Posted: Wed Jun 12, 2013 11:58 am
by jeremiahnz
torqued wrote:My Rx7 calipers are almost flush.
If they didnt have the fluid bridge that extends outside the caliper they would be
Yep - part of my issue will be related to the Evo rotor I am using which has a low top hat height. I choose them specifically to keep the caliper forward, so the back of it doesn't foul on the suspension.

Also found this Evo build thread that shows an example that looks worse than mine:
Image

Any body got any thoughts on the bleed nipple on the caliper facing down, as opposed to up? Will this cause be cert/functionality issues?

Thanks

Re: Front caliper clearance and bleed

Posted: Wed Jun 12, 2013 12:07 pm
by DJZ
Only when you go to bleed the brakes, but you can always pull them off and either place them on the rotor up the other way and bleed them normally or leave them loose and use a vacuum bleeder. Not sure whether it'll be a cert issue.

I don't know whether it helps or not but I've ground out the inside of the wheels on the front of the DR as they wouldn't clear the spigot part of the hubs, you could do this then get some spacers with bigger OD hubcentric rings?

Re: Front caliper clearance and bleed

Posted: Wed Jun 12, 2013 1:25 pm
by jeremiahnz
DJZ wrote: I don't know whether it helps or not but I've ground out the inside of the wheels on the front of the DR as they wouldn't clear the spigot part of the hubs, you could do this then get some spacers with bigger OD hubcentric rings?
Thanks. I thought about this but as the hub OD is already 73mm, I'd need to go larger on the hubcentric spacers which would likely mean modifying wheels as well (I believe most aftermarket wheels go up to around 73mm ID). I'd also need custom spacers as the largest OD of the hub centric lip seems to be 73mm (for readily available products)

Re: Front caliper clearance and bleed

Posted: Thu Jun 13, 2013 2:01 pm
by Godzilladat
I have been thinking about what to do in terms of front braking for my 411. I'm currently keeping my eyes open for a complete replacement spindle that is similar in size.

The bearings and setup are so restrictive on the 410/411, so if I can achieve what I need by replacing the whole unit it would be a better result. I know you have put a lot of work into making it happen with the stock hub & spindle, but I'm hoping I can achieve the same with a replacement spindle.