Cheap 99-00 chassis bracing upgrade

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2001 BJFP MT
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2016 BMYFS AT
I made a discovery last night while flipping through the shop manual... it says that the rear crossmember support bracket was added in 2001. In otherwords, 99-00s don't have this!

I just can't imagine not having this cheap, but crucial part (it came with my 2001, of course). It sits between the bottom of the floor and the center portion of the rear crossmember. Its purpose is to reduce the rear crossmember flex in order to stabilize the rear suspension geometry under load. As with all chassis bracing, that is it's main purpose; to maintain suspension geometry in order to provide stable, predictable handling.

So for many of you 99-00 owners who weren't fortunate enough to have the Autoexe chassis braces, this is the next best thing. Here in the US, it's a mere $20 part, so you might be able to find one from the junk yard for next to nothing!

Here is what the part looks like:
crossmember%2520support%2520bracket.jpg

There are also 5 bolts that goes with it

It goes here (the red Autoexe piece you see replaces it; I didn't bother taking pics of my stock one on the car):
DSCN2308.jpg


Installation is very easy.
First, remove the 4 bolts for the rear crossmember, and lower it with everything still attached. Do NOT touch the lateral link bolts if you don't want to get an alignment done again.
Afterwards, bolt the support bracket into the bottom of the floor with 3 bolts. The opening side where you can insert the bolts are towards the fuel tank.
Finally, just raise the crossmember back up with a jack or with help of another person very slowly/carefully, then bolt the crossmember back on the car and bolt the bottom side of the support bracket through the openings at the bottom of the crossmember. :) There are 2 alignment/centering pins on each side where the crossmember bolts to the car, so its position will practically be the same as before.

If you installed the MSP sway bar kit on your 99-00, YOU NEED THIS in order for you to get the full potential from your suspension upgrades!!


Any of you who want to just buy this cheap part new, the part number is B30D-28-8C0. You will need 5 bolts, in which the part number is 9078-60-820.


Other chassis stiffening improvements Mazda put in 2001 was the front strut tower stiffeners (the black metal plates that sits on top of the strut towers) but not worth mentioning because a strut bar does a lot more, and the lower tie brace in the front crossmember (the GT spec 4 point ladder brace replaces this). Installation of the OEM lower tie brace or GT spec ladder brace requires changing the front crossmember out completely because the mounting holes are not there in the 99-00! Do this only when you install a bigger sway bar or swap engines, otherwise, it's not even worth your time.
 
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Sweet thanks man i upgraded my sway bar ill probably just end up buying it new since all the cars at the junk yard are all 99-00 i have yet to see 1 p5 or even a 01-03...this is next on my list pf parts.
 
Thank you sir! I wil be ordering this next week. I think I will get the one for the P5, I have the racing beat rear sway bar and GT Spec trunk cage so I hear alot of squeaking back there...

I know speedracer flipped when he found this thread... I sure did!
 
be sure to post back with some pics and results ;)
it'll be a good opportunity to lube those sway bar bushings then too... I use the energy suspension grease... I never failed me yet! I got lazy and didn't lube the bushings for like 4 years... took the bushings out, still looks great... only a little bit of paint rubbed off on the sway bar, 90% of the paint still there under the bushings!

EDIT: Pick n Pull shows that their San Antonio yard has a 2001 Protege... so go check it out! One of you will obviously need to buy a new one, so I guess it's a good opportunity to compare the sedan piece and the P5 one ;)
you might want to grab other bits from it too, such as the front crossmember, brakes, and other better crap
 
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So if i swap the front crossmember i can use the 4pt ladder brace ive been wanting one but it wont fit the 99-00. And as for the brace ill probably just buy a new one the yard is clear across town for me but if the cross member will work so i can use the ladder brace i might make the trip.
 
yes, swapping the crossmember will let you put the 4 point brace on
don't forget to get an alignment done afterwards
the 01-03 also have stiffer suspension bushings
 
Sweet thanks man i upgraded my sway bar ill probably just end up buying it new since all the cars at the junk yard are all 99-00 i have yet to see 1 p5 or even a 01-03...this is next on my list pf parts.
I just left pick-n-pull. They have 2 of the 2001+ protege there and both have the front subframe. I grabbed the rear subframe bracket and bolts for $10.94. On the way home I stopped at Mazda and they said both parts are discontinued. They gave me prices, the sedan part was $20 and the one for the P5 was $35 list price. Those prices are irrelevent, just wanted to know if they were even available from Mazda.
 
it didn't say discontinued when I checked this morning... just that they're indefinitely back ordered
so you *could* try to order from a place like onlinemazdaparts.com and just wait till whenever it arrives
 
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You know how the people in the parts department are, the system says back order, they say discontinued... LOL thats how the dealers are... I would know, I work for one... I am just glad i finally found one in the junk yard, thanks for the heads up on pick-n-pull... @TheMAN Are you going to be at the state wide mazda meet in DFW?
 
I think so
I got another mod on the way in the mail right now, one more thing to get "prepared"

so you mean that's how YOUR dealers are? lol
we have good mazda dealers here
 
Well i guess ill just have to swing by pick and pull then and grab both subframes front and rear ive never removed the front is it as easy as the rear. Are the subframes the same on the 99-00 and the 01-03 so all i would need is the brace not the whole subframe i dont want to buy it if i dont need the rear.
 
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Well i guess ill just have to swing by pick and pull then and grab both subframes front and rear ive never removed the front is it as easy as the rear. Are the subframes the same on the 99-00 and the 01-03 so all i would need is the brace not the whole subframe i dont want to buy it if i dont need the rear.
You need the whole front subframe. The ones our cars have no threaded holes for the 4 point brace to bolt to... The cars at pick-n-pull still have engines hanging in there, just drop that bad boy out and unbolt the rack from the subframe and you are almost done. Just take out the bolts that hold the subframe to the body and the whole subframe drops out, you are good to go.

I was installing my rear subframe brace and i ran into the same problem. My car had holes in the subframe to bolt the brace to, but the top bolts had no home. I am going to drill out very small holes in the under body and tap them with good threads. Right now the brace is just in with the bottom 2 bolts, but it still feels like it improved the rear. At least not as many squeaks for sure... Here are some pics...

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You need the whole front subframe. The ones our cars have no threaded holes for the 4 point brace to bolt to... The cars at pick-n-pull still have engines hanging in there, just drop that bad boy out and unbolt the rack from the subframe and you are almost done. Just take out the bolts that hold the subframe to the body and the whole subframe drops out, you are good to go.

I was installing my rear subframe brace and i ran into the same problem. My car had holes in the subframe to bolt the brace to, but the top bolts had no home. I am going to drill out very small holes in the under body and tap them with good threads. Right now the brace is just in with the bottom 2 bolts, but it still feels like it improved the rear. At least not as many squeaks for sure... Here are some pics...

this answers some questions.... was your car built before June 15, 1999? If so, then that crossbeam in the rear floor is different than the later builds. The later ones should have the holes in it
you might want to just use some anchoring bolts instead (the ones you buy at the hardware store that have the spring loaded thingys)... or cut a hole to insert some nuts on the back side and weld/bolt them into place
 
Very interesting find TheMan. I'll look into the P5 brace. Speed & Reichle when ya'll have time I'd like to compare my 2001 to your cars. To see how things changed from one year to the next.
 
build date

I just checked and my car was built in 3/1999. Now I just need some self anchoring bolts. To secure the top of the bracket to the body...
 
you could also do this... take the carpet off in the trunk
drill through the crossframe and through the floorboard

insert a bolt from the trunk... use nut, lock washer, and flat washer from the bottom
DONE

that's what I'll probably do if I were you... easier, faster to do, more secure, and you won't even see it once the carpet is back on
yes, drill from the bottom of the car UPWARDS into the trunk! DO NOT drill from the trunk, you risk drilling into the gas tank!
want to keep the bolts lower profile/smoother so you won't have 3 lumps in the middle of the trunk floor? use allen head or torx bolts... or just get some carriage bolts and tack weld them into place, that way you won't even need a helper from up top to hold the bolts while you tighten from the bottom

one alternative idea... drill through the floor as mentioned, then widen up the holes up top so that you can insert nuts from the trunk down to the inside of the crossframe... tack weld them on or just have a helper hold them in place while you thread the OEM bolts on from the bottom, then tighten.... afterwards, just get some rubber plugs to cover up those holes in the trunk to keep out water ;)

don't forget to fold the seats down because that crossframe is pretty close to the back seats!
 
oh yeah... are those cars at the junk yard an ES or P5?
if so you can do a rear brake swap... but here's an idea to do it WITHOUT having to go 5 lugs... get all the parts you need as others have said before (lateral links, e-brake cable, caliper, and spindle assembly)
you then swap your stock wheel bearings into the ES/P5 spindle

afterwards, go buy yourself a set of JDM rotors from corksport or someone else (part # for rotor on my site)

DONE

still much cheaper than buying new rims
 
you could also do this... take the carpet off in the trunk
drill through the crossframe and through the floorboard

insert a bolt from the trunk... use nut, lock washer, and flat washer from the bottom
DONE

that's what I'll probably do if I were you... easier, faster to do, more secure, and you won't even see it once the carpet is back on
yes, drill from the bottom of the car UPWARDS into the trunk! DO NOT drill from the trunk, you risk drilling into the gas tank!
want to keep the bolts lower profile/smoother so you won't have 3 lumps in the middle of the trunk floor? use allen head or torx bolts... or just get some carriage bolts and tack weld them into place, that way you won't even need a helper from up top to hold the bolts while you tighten from the bottom

one alternative idea... drill through the floor as mentioned, then widen up the holes up top so that you can insert nuts from the trunk down to the inside of the crossframe... tack weld them on or just have a helper hold them in place while you thread the OEM bolts on from the bottom, then tighten.... afterwards, just get some rubber plugs to cover up those holes in the trunk to keep out water ;)

don't forget to fold the seats down because that crossframe is pretty close to the back seats!

oh yeah... are those cars at the junk yard an ES or P5?
if so you can do a rear brake swap... but here's an idea to do it WITHOUT having to go 5 lugs... get all the parts you need as others have said before (lateral links, e-brake cable, caliper, and spindle assembly)
you then swap your stock wheel bearings into the ES/P5 spindle

afterwards, go buy yourself a set of JDM rotors from corksport or someone else (part # for rotor on my site)

DONE

still much cheaper than buying new rims

hm thats an idea i might have to try that id like discs in the rear but dont want to go 5lug. Im sure the cars ar just the sedans no p5's but ill get them anyways if they are the es ones and give it a shot. i though about doing that wondered if it would work. I just got some es front brakes the other day with drilled rotors
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